diff --git a/.gitignore b/.gitignore
index 1c9a181..1584f38 100644
--- a/.gitignore
+++ b/.gitignore
@@ -240,3 +240,5 @@ ModelManifest.xml
 
 # FAKE - F# Make
 .fake/
+
+DotNetValidationDemo_v13\.zip
diff --git a/App.config b/App.config
index 6850fc2..fa344e6 100644
--- a/App.config
+++ b/App.config
@@ -1,7 +1,7 @@
-<?xml version="1.0" encoding="utf-8" ?>
+<?xml version="1.0" encoding="utf-8"?>
 <configuration>
     <configSections>
-        <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" >
+        <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
             <section name="Furore.Fhir.ValidationDemo.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" allowExeDefinition="MachineToLocalUser" requirePermission="false" />
         </sectionGroup>
     </configSections>
@@ -16,6 +16,35 @@
             <setting name="InstanceXml" serializeAs="String">
                 <value />
             </setting>
+            <setting name="TerminologyService" serializeAs="String">
+                <value />
+            </setting>
+            <setting name="UseBuiltInTX" serializeAs="String">
+                <value>True</value>
+            </setting>
+            <setting name="TerminologyServiceList" serializeAs="String">
+                <value>http://ontoserver.csiro.au/stu3-latest|http://tx.fhir.org/r3</value>
+            </setting>
+            <setting name="EnableTrace" serializeAs="String">
+                <value>False</value>
+            </setting>
+            <setting name="DoXsdValidation" serializeAs="String">
+                <value>False</value>
+            </setting>
+            <setting name="DisableFP" serializeAs="String">
+                <value>False</value>
+            </setting>
+            <setting name="RegenerateSnapshot" serializeAs="String">
+                <value>False</value>
+            </setting>
         </Furore.Fhir.ValidationDemo.Properties.Settings>
     </userSettings>
+  <runtime>
+    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
+      <dependentAssembly>
+        <assemblyIdentity name="System.ValueTuple" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.2.0" newVersion="4.0.2.0" />
+      </dependentAssembly>
+    </assemblyBinding>
+  </runtime>
 </configuration>
\ No newline at end of file
diff --git a/Furore.Fhir.ValidationDemo.csproj b/Furore.Fhir.ValidationDemo.csproj
index 323d4ad..47b88ba 100644
--- a/Furore.Fhir.ValidationDemo.csproj
+++ b/Furore.Fhir.ValidationDemo.csproj
@@ -32,12 +32,26 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="Hl7.Fhir.DSTU2.Core, Version=0.92.5.0, Culture=neutral, PublicKeyToken=d706911480550fc3, processorArchitecture=MSIL">
+      <HintPath>packages\Hl7.Fhir.DSTU2.0.92.5-beta3\lib\net45\Hl7.Fhir.DSTU2.Core.dll</HintPath>
+    </Reference>
+    <Reference Include="Hl7.Fhir.DSTU2.Specification, Version=0.92.5.0, Culture=neutral, PublicKeyToken=d706911480550fc3, processorArchitecture=MSIL">
+      <HintPath>packages\Hl7.Fhir.Specification.DSTU2.0.92.5-beta3\lib\net45\Hl7.Fhir.DSTU2.Specification.dll</HintPath>
+    </Reference>
+    <Reference Include="Hl7.Fhir.Support, Version=0.4.4.0, Culture=neutral, PublicKeyToken=d706911480550fc3, processorArchitecture=MSIL">
+      <HintPath>packages\Hl7.Fhir.Support.0.4.4-beta3\lib\net45\Hl7.Fhir.Support.dll</HintPath>
+    </Reference>
+    <Reference Include="Hl7.FhirPath, Version=0.4.4.0, Culture=neutral, PublicKeyToken=d706911480550fc3, processorArchitecture=MSIL">
+      <HintPath>packages\Hl7.FhirPath.0.4.4-beta3\lib\net45\Hl7.FhirPath.dll</HintPath>
+    </Reference>
     <Reference Include="Newtonsoft.Json, Version=9.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
       <HintPath>packages\Newtonsoft.Json.9.0.1\lib\net45\Newtonsoft.Json.dll</HintPath>
-      <Private>True</Private>
     </Reference>
     <Reference Include="System" />
     <Reference Include="System.Core" />
+    <Reference Include="System.ValueTuple, Version=4.0.2.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
+      <HintPath>packages\System.ValueTuple.4.4.0-preview2-25405-01\lib\netstandard1.0\System.ValueTuple.dll</HintPath>
+    </Reference>
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />
@@ -57,6 +71,12 @@
     </Compile>
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="SettingsForm.cs">
+      <SubType>Form</SubType>
+    </Compile>
+    <Compile Include="SettingsForm.Designer.cs">
+      <DependentUpon>SettingsForm.cs</DependentUpon>
+    </Compile>
     <EmbeddedResource Include="MainForm.resx">
       <DependentUpon>MainForm.cs</DependentUpon>
     </EmbeddedResource>
@@ -69,6 +89,9 @@
       <AutoGen>True</AutoGen>
       <DependentUpon>Resources.resx</DependentUpon>
     </Compile>
+    <EmbeddedResource Include="SettingsForm.resx">
+      <DependentUpon>SettingsForm.cs</DependentUpon>
+    </EmbeddedResource>
     <None Include="packages.config">
       <SubType>Designer</SubType>
     </None>
@@ -81,24 +104,13 @@
       <DependentUpon>Settings.settings</DependentUpon>
       <DesignTimeSharedInput>True</DesignTimeSharedInput>
     </Compile>
+    <None Include="specification.zip">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
   </ItemGroup>
   <ItemGroup>
     <None Include="App.config" />
   </ItemGroup>
-  <ItemGroup>
-    <ProjectReference Include="..\fhir-net-api\src\Hl7.Fhir.Core\Hl7.Fhir.Core.csproj">
-      <Project>{7C9F23BF-498C-40AA-80CF-D495CE58D246}</Project>
-      <Name>Hl7.Fhir.Core</Name>
-    </ProjectReference>
-    <ProjectReference Include="..\fhir-net-api\src\Hl7.Fhir.Specification\Hl7.Fhir.Specification.csproj">
-      <Project>{61AF8F62-C4AA-4A5F-A7D5-76021A300D09}</Project>
-      <Name>Hl7.Fhir.Specification</Name>
-    </ProjectReference>
-    <ProjectReference Include="..\fhir-net-api\src\Hl7.Fhir.Support\Hl7.Fhir.Support.csproj">
-      <Project>{8e194124-0629-4059-a084-fd42fcb6ca42}</Project>
-      <Name>Hl7.Fhir.Support</Name>
-    </ProjectReference>
-  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
diff --git a/Furore.Fhir.ValidationDemo.sln b/Furore.Fhir.ValidationDemo.sln
index 92151bc..3a1ec04 100644
--- a/Furore.Fhir.ValidationDemo.sln
+++ b/Furore.Fhir.ValidationDemo.sln
@@ -1,18 +1,10 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.26430.14
+VisualStudioVersion = 15.0.26430.6
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Furore.Fhir.ValidationDemo", "Furore.Fhir.ValidationDemo.csproj", "{655AE501-2657-42F5-A1B5-4DBE94D5AB05}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Hl7.Fhir.Core", "..\fhir-net-api\src\Hl7.Fhir.Core\Hl7.Fhir.Core.csproj", "{7C9F23BF-498C-40AA-80CF-D495CE58D246}"
-EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Hl7.Fhir.Specification", "..\fhir-net-api\src\Hl7.Fhir.Specification\Hl7.Fhir.Specification.csproj", "{61AF8F62-C4AA-4A5F-A7D5-76021A300D09}"
-EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Hl7.Fhir.Support", "..\fhir-net-api\src\Hl7.Fhir.Support\Hl7.Fhir.Support.csproj", "{8E194124-0629-4059-A084-FD42FCB6CA42}"
-EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Hl7.FhirPath", "..\fhir-net-api\src\Hl7.FhirPath\Hl7.FhirPath.csproj", "{2B1B6B23-7FAB-4612-80A4-508C302C75F5}"
-EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -23,22 +15,6 @@ Global
 		{655AE501-2657-42F5-A1B5-4DBE94D5AB05}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{655AE501-2657-42F5-A1B5-4DBE94D5AB05}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{655AE501-2657-42F5-A1B5-4DBE94D5AB05}.Release|Any CPU.Build.0 = Release|Any CPU
-		{7C9F23BF-498C-40AA-80CF-D495CE58D246}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{7C9F23BF-498C-40AA-80CF-D495CE58D246}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{7C9F23BF-498C-40AA-80CF-D495CE58D246}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{7C9F23BF-498C-40AA-80CF-D495CE58D246}.Release|Any CPU.Build.0 = Release|Any CPU
-		{61AF8F62-C4AA-4A5F-A7D5-76021A300D09}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{61AF8F62-C4AA-4A5F-A7D5-76021A300D09}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{61AF8F62-C4AA-4A5F-A7D5-76021A300D09}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{61AF8F62-C4AA-4A5F-A7D5-76021A300D09}.Release|Any CPU.Build.0 = Release|Any CPU
-		{8E194124-0629-4059-A084-FD42FCB6CA42}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{8E194124-0629-4059-A084-FD42FCB6CA42}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{8E194124-0629-4059-A084-FD42FCB6CA42}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{8E194124-0629-4059-A084-FD42FCB6CA42}.Release|Any CPU.Build.0 = Release|Any CPU
-		{2B1B6B23-7FAB-4612-80A4-508C302C75F5}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{2B1B6B23-7FAB-4612-80A4-508C302C75F5}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{2B1B6B23-7FAB-4612-80A4-508C302C75F5}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{2B1B6B23-7FAB-4612-80A4-508C302C75F5}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/MainForm.Designer.cs b/MainForm.Designer.cs
index 714b5c7..a04c78e 100644
--- a/MainForm.Designer.cs
+++ b/MainForm.Designer.cs
@@ -28,155 +28,72 @@ protected override void Dispose(bool disposing)
         /// </summary>
         private void InitializeComponent()
         {
-            this.groupBox1 = new System.Windows.Forms.GroupBox();
-            this.label2 = new System.Windows.Forms.Label();
-            this.btnReload = new System.Windows.Forms.Button();
-            this.btnOpenProfileDir = new System.Windows.Forms.Button();
-            this.txtProfileDirectory = new System.Windows.Forms.TextBox();
-            this.label1 = new System.Windows.Forms.Label();
-            this.groupBox2 = new System.Windows.Forms.GroupBox();
-            this.chkDisableFP = new System.Windows.Forms.CheckBox();
-            this.chkShowTraceInfo = new System.Windows.Forms.CheckBox();
-            this.chkXsdValidation = new System.Windows.Forms.CheckBox();
+            this.instanceBox = new System.Windows.Forms.GroupBox();
+            this.btnLoad = new System.Windows.Forms.Button();
             this.btnValidate = new System.Windows.Forms.Button();
             this.txtInstanceXml = new System.Windows.Forms.RichTextBox();
             this.groupBox3 = new System.Windows.Forms.GroupBox();
+            this.flowLayoutPanel1 = new System.Windows.Forms.FlowLayoutPanel();
+            this.cbErrors = new System.Windows.Forms.CheckBox();
+            this.cbWarnings = new System.Windows.Forms.CheckBox();
+            this.cbInformation = new System.Windows.Forms.CheckBox();
+            this.btnCopyClipboard = new System.Windows.Forms.Button();
             this.txtOutcome = new System.Windows.Forms.TextBox();
-            this.folderBrowserDialog = new System.Windows.Forms.FolderBrowserDialog();
-            this.groupBox1.SuspendLayout();
-            this.groupBox2.SuspendLayout();
+            this.mainStrip = new System.Windows.Forms.StatusStrip();
+            this.mainStatusLabel = new System.Windows.Forms.ToolStripStatusLabel();
+            this.groupBox1 = new System.Windows.Forms.GroupBox();
+            this.chkGenSnapshot = new System.Windows.Forms.CheckBox();
+            this.chkDisableFP = new System.Windows.Forms.CheckBox();
+            this.chkShowTraceInfo = new System.Windows.Forms.CheckBox();
+            this.chkXsdValidation = new System.Windows.Forms.CheckBox();
+            this.btnReload = new System.Windows.Forms.Button();
+            this.btnSettings = new System.Windows.Forms.Button();
+            this.lblTerminologySvc = new System.Windows.Forms.Label();
+            this.label2 = new System.Windows.Forms.Label();
+            this.lblDefinitionPath = new System.Windows.Forms.Label();
+            this.label1 = new System.Windows.Forms.Label();
+            this.openInstance = new System.Windows.Forms.OpenFileDialog();
+            this.instanceBox.SuspendLayout();
             this.groupBox3.SuspendLayout();
+            this.flowLayoutPanel1.SuspendLayout();
+            this.mainStrip.SuspendLayout();
+            this.groupBox1.SuspendLayout();
             this.SuspendLayout();
             // 
-            // groupBox1
-            // 
-            this.groupBox1.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
-            | System.Windows.Forms.AnchorStyles.Right)));
-            this.groupBox1.Controls.Add(this.label2);
-            this.groupBox1.Controls.Add(this.btnReload);
-            this.groupBox1.Controls.Add(this.btnOpenProfileDir);
-            this.groupBox1.Controls.Add(this.txtProfileDirectory);
-            this.groupBox1.Controls.Add(this.label1);
-            this.groupBox1.Location = new System.Drawing.Point(12, 12);
-            this.groupBox1.Name = "groupBox1";
-            this.groupBox1.Size = new System.Drawing.Size(629, 147);
-            this.groupBox1.TabIndex = 0;
-            this.groupBox1.TabStop = false;
-            this.groupBox1.Text = "Profile source directory";
-            // 
-            // label2
-            // 
-            this.label2.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
-            | System.Windows.Forms.AnchorStyles.Right)));
-            this.label2.Location = new System.Drawing.Point(6, 78);
-            this.label2.Name = "label2";
-            this.label2.Size = new System.Drawing.Size(617, 33);
-            this.label2.TabIndex = 4;
-            this.label2.Text = "For performance reasons, profiles in this directory will not be re-scanned on eac" +
-    "h validation run. Press \'Reload\' to refresh the cached information the validator" +
-    " may have.";
-            // 
-            // btnReload
-            // 
-            this.btnReload.Location = new System.Drawing.Point(9, 112);
-            this.btnReload.Name = "btnReload";
-            this.btnReload.Size = new System.Drawing.Size(75, 23);
-            this.btnReload.TabIndex = 3;
-            this.btnReload.Text = "Reload";
-            this.btnReload.UseVisualStyleBackColor = true;
-            this.btnReload.Click += new System.EventHandler(this.btnReload_Click);
+            // instanceBox
             // 
-            // btnOpenProfileDir
-            // 
-            this.btnOpenProfileDir.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
-            this.btnOpenProfileDir.Location = new System.Drawing.Point(548, 39);
-            this.btnOpenProfileDir.Name = "btnOpenProfileDir";
-            this.btnOpenProfileDir.Size = new System.Drawing.Size(75, 23);
-            this.btnOpenProfileDir.TabIndex = 2;
-            this.btnOpenProfileDir.Text = "Browse...";
-            this.btnOpenProfileDir.UseVisualStyleBackColor = true;
-            this.btnOpenProfileDir.Click += new System.EventHandler(this.btnOpenProfileDir_Click);
-            // 
-            // txtProfileDirectory
-            // 
-            this.txtProfileDirectory.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
-            | System.Windows.Forms.AnchorStyles.Right)));
-            this.txtProfileDirectory.DataBindings.Add(new System.Windows.Forms.Binding("Text", global::Furore.Fhir.ValidationDemo.Properties.Settings.Default, "ProfileSourceDirectory", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
-            this.txtProfileDirectory.Location = new System.Drawing.Point(6, 42);
-            this.txtProfileDirectory.Name = "txtProfileDirectory";
-            this.txtProfileDirectory.Size = new System.Drawing.Size(536, 20);
-            this.txtProfileDirectory.TabIndex = 1;
-            this.txtProfileDirectory.Text = global::Furore.Fhir.ValidationDemo.Properties.Settings.Default.ProfileSourceDirectory;
-            this.txtProfileDirectory.TextChanged += new System.EventHandler(this.txtProfileDirectory_TextChanged);
-            // 
-            // label1
-            // 
-            this.label1.AutoSize = true;
-            this.label1.Location = new System.Drawing.Point(6, 26);
-            this.label1.Name = "label1";
-            this.label1.Size = new System.Drawing.Size(421, 13);
-            this.label1.TabIndex = 0;
-            this.label1.Text = "The validator will look for your profiles and other conformance resources in this" +
-    " directory:";
-            // 
-            // groupBox2
-            // 
-            this.groupBox2.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) 
+            this.instanceBox.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) 
             | System.Windows.Forms.AnchorStyles.Left) 
             | System.Windows.Forms.AnchorStyles.Right)));
-            this.groupBox2.Controls.Add(this.chkDisableFP);
-            this.groupBox2.Controls.Add(this.chkShowTraceInfo);
-            this.groupBox2.Controls.Add(this.chkXsdValidation);
-            this.groupBox2.Controls.Add(this.btnValidate);
-            this.groupBox2.Controls.Add(this.txtInstanceXml);
-            this.groupBox2.Location = new System.Drawing.Point(13, 175);
-            this.groupBox2.Name = "groupBox2";
-            this.groupBox2.Size = new System.Drawing.Size(627, 281);
-            this.groupBox2.TabIndex = 1;
-            this.groupBox2.TabStop = false;
-            this.groupBox2.Text = "Instance (xml)";
-            // 
-            // chkDisableFP
-            // 
-            this.chkDisableFP.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
-            this.chkDisableFP.AutoSize = true;
-            this.chkDisableFP.Location = new System.Drawing.Point(437, 249);
-            this.chkDisableFP.Name = "chkDisableFP";
-            this.chkDisableFP.Size = new System.Drawing.Size(115, 17);
-            this.chkDisableFP.TabIndex = 8;
-            this.chkDisableFP.Text = "Disable FP checks";
-            this.chkDisableFP.UseVisualStyleBackColor = true;
-            // 
-            // chkShowTraceInfo
-            // 
-            this.chkShowTraceInfo.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
-            this.chkShowTraceInfo.AutoSize = true;
-            this.chkShowTraceInfo.Location = new System.Drawing.Point(140, 249);
-            this.chkShowTraceInfo.Name = "chkShowTraceInfo";
-            this.chkShowTraceInfo.Size = new System.Drawing.Size(142, 17);
-            this.chkShowTraceInfo.TabIndex = 7;
-            this.chkShowTraceInfo.Text = "Include trace information";
-            this.chkShowTraceInfo.UseVisualStyleBackColor = true;
-            // 
-            // chkXsdValidation
-            // 
-            this.chkXsdValidation.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
-            this.chkXsdValidation.AutoSize = true;
-            this.chkXsdValidation.Location = new System.Drawing.Point(302, 249);
-            this.chkXsdValidation.Name = "chkXsdValidation";
-            this.chkXsdValidation.Size = new System.Drawing.Size(115, 17);
-            this.chkXsdValidation.TabIndex = 6;
-            this.chkXsdValidation.Text = "Run Xsd validation";
-            this.chkXsdValidation.UseVisualStyleBackColor = true;
+            this.instanceBox.Controls.Add(this.btnLoad);
+            this.instanceBox.Controls.Add(this.btnValidate);
+            this.instanceBox.Controls.Add(this.txtInstanceXml);
+            this.instanceBox.Location = new System.Drawing.Point(13, 11);
+            this.instanceBox.Name = "instanceBox";
+            this.instanceBox.Size = new System.Drawing.Size(767, 248);
+            this.instanceBox.TabIndex = 1;
+            this.instanceBox.TabStop = false;
+            this.instanceBox.Text = "Instance";
+            // 
+            // btnLoad
+            // 
+            this.btnLoad.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
+            this.btnLoad.Location = new System.Drawing.Point(669, 216);
+            this.btnLoad.Name = "btnLoad";
+            this.btnLoad.Size = new System.Drawing.Size(88, 23);
+            this.btnLoad.TabIndex = 7;
+            this.btnLoad.Text = "Load...";
+            this.btnLoad.UseVisualStyleBackColor = true;
+            this.btnLoad.Click += new System.EventHandler(this.btnLoad_Click);
             // 
             // btnValidate
             // 
             this.btnValidate.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
-            this.btnValidate.Location = new System.Drawing.Point(9, 243);
+            this.btnValidate.Location = new System.Drawing.Point(9, 216);
             this.btnValidate.Name = "btnValidate";
             this.btnValidate.Size = new System.Drawing.Size(75, 23);
-            this.btnValidate.TabIndex = 5;
-            this.btnValidate.Text = "Validate!";
+            this.btnValidate.TabIndex = 6;
+            this.btnValidate.Text = "&Validate!";
             this.btnValidate.UseVisualStyleBackColor = true;
             this.btnValidate.Click += new System.EventHandler(this.btnValidate_Click);
             // 
@@ -189,22 +106,89 @@ private void InitializeComponent()
             this.txtInstanceXml.DataBindings.Add(new System.Windows.Forms.Binding("Text", global::Furore.Fhir.ValidationDemo.Properties.Settings.Default, "InstanceXml", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
             this.txtInstanceXml.Location = new System.Drawing.Point(9, 23);
             this.txtInstanceXml.Name = "txtInstanceXml";
-            this.txtInstanceXml.Size = new System.Drawing.Size(608, 208);
+            this.txtInstanceXml.Size = new System.Drawing.Size(748, 187);
             this.txtInstanceXml.TabIndex = 0;
             this.txtInstanceXml.Text = global::Furore.Fhir.ValidationDemo.Properties.Settings.Default.InstanceXml;
+            this.txtInstanceXml.TextChanged += new System.EventHandler(this.txtInstanceXml_TextChanged);
             // 
             // groupBox3
             // 
             this.groupBox3.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left) 
             | System.Windows.Forms.AnchorStyles.Right)));
+            this.groupBox3.Controls.Add(this.flowLayoutPanel1);
+            this.groupBox3.Controls.Add(this.btnCopyClipboard);
             this.groupBox3.Controls.Add(this.txtOutcome);
-            this.groupBox3.Location = new System.Drawing.Point(12, 462);
+            this.groupBox3.Location = new System.Drawing.Point(12, 275);
             this.groupBox3.Name = "groupBox3";
-            this.groupBox3.Size = new System.Drawing.Size(627, 209);
+            this.groupBox3.Size = new System.Drawing.Size(767, 218);
             this.groupBox3.TabIndex = 2;
             this.groupBox3.TabStop = false;
             this.groupBox3.Text = "Last Validation results";
             // 
+            // flowLayoutPanel1
+            // 
+            this.flowLayoutPanel1.Controls.Add(this.cbErrors);
+            this.flowLayoutPanel1.Controls.Add(this.cbWarnings);
+            this.flowLayoutPanel1.Controls.Add(this.cbInformation);
+            this.flowLayoutPanel1.Location = new System.Drawing.Point(7, 181);
+            this.flowLayoutPanel1.Name = "flowLayoutPanel1";
+            this.flowLayoutPanel1.Size = new System.Drawing.Size(327, 31);
+            this.flowLayoutPanel1.TabIndex = 10;
+            // 
+            // cbErrors
+            // 
+            this.cbErrors.Appearance = System.Windows.Forms.Appearance.Button;
+            this.cbErrors.AutoSize = true;
+            this.cbErrors.Checked = true;
+            this.cbErrors.CheckState = System.Windows.Forms.CheckState.Checked;
+            this.cbErrors.FlatStyle = System.Windows.Forms.FlatStyle.Popup;
+            this.cbErrors.Location = new System.Drawing.Point(3, 3);
+            this.cbErrors.Name = "cbErrors";
+            this.cbErrors.Size = new System.Drawing.Size(44, 23);
+            this.cbErrors.TabIndex = 8;
+            this.cbErrors.Text = "Errors";
+            this.cbErrors.UseVisualStyleBackColor = true;
+            this.cbErrors.CheckedChanged += new System.EventHandler(this.cbOutcomeFilter_CheckedChanged);
+            // 
+            // cbWarnings
+            // 
+            this.cbWarnings.Appearance = System.Windows.Forms.Appearance.Button;
+            this.cbWarnings.AutoSize = true;
+            this.cbWarnings.Checked = true;
+            this.cbWarnings.CheckState = System.Windows.Forms.CheckState.Checked;
+            this.cbWarnings.FlatStyle = System.Windows.Forms.FlatStyle.Popup;
+            this.cbWarnings.Location = new System.Drawing.Point(53, 3);
+            this.cbWarnings.Name = "cbWarnings";
+            this.cbWarnings.Size = new System.Drawing.Size(62, 23);
+            this.cbWarnings.TabIndex = 9;
+            this.cbWarnings.Text = "Warnings";
+            this.cbWarnings.UseVisualStyleBackColor = true;
+            this.cbWarnings.CheckedChanged += new System.EventHandler(this.cbOutcomeFilter_CheckedChanged);
+            // 
+            // cbInformation
+            // 
+            this.cbInformation.Appearance = System.Windows.Forms.Appearance.Button;
+            this.cbInformation.AutoSize = true;
+            this.cbInformation.FlatStyle = System.Windows.Forms.FlatStyle.Popup;
+            this.cbInformation.Location = new System.Drawing.Point(121, 3);
+            this.cbInformation.Name = "cbInformation";
+            this.cbInformation.Size = new System.Drawing.Size(69, 23);
+            this.cbInformation.TabIndex = 10;
+            this.cbInformation.Text = "Information";
+            this.cbInformation.UseVisualStyleBackColor = true;
+            this.cbInformation.CheckedChanged += new System.EventHandler(this.cbOutcomeFilter_CheckedChanged);
+            // 
+            // btnCopyClipboard
+            // 
+            this.btnCopyClipboard.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
+            this.btnCopyClipboard.Location = new System.Drawing.Point(640, 185);
+            this.btnCopyClipboard.Name = "btnCopyClipboard";
+            this.btnCopyClipboard.Size = new System.Drawing.Size(118, 27);
+            this.btnCopyClipboard.TabIndex = 6;
+            this.btnCopyClipboard.Text = "Copy to clipboard";
+            this.btnCopyClipboard.UseVisualStyleBackColor = true;
+            this.btnCopyClipboard.Click += new System.EventHandler(this.btnCopyClipboard_Click);
+            // 
             // txtOutcome
             // 
             this.txtOutcome.AcceptsTab = true;
@@ -216,55 +200,224 @@ private void InitializeComponent()
             this.txtOutcome.Name = "txtOutcome";
             this.txtOutcome.ReadOnly = true;
             this.txtOutcome.ScrollBars = System.Windows.Forms.ScrollBars.Both;
-            this.txtOutcome.Size = new System.Drawing.Size(608, 172);
+            this.txtOutcome.Size = new System.Drawing.Size(748, 159);
             this.txtOutcome.TabIndex = 0;
             // 
-            // folderBrowserDialog
+            // mainStrip
+            // 
+            this.mainStrip.ImageScalingSize = new System.Drawing.Size(32, 32);
+            this.mainStrip.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
+            this.mainStatusLabel});
+            this.mainStrip.Location = new System.Drawing.Point(0, 656);
+            this.mainStrip.Name = "mainStrip";
+            this.mainStrip.Size = new System.Drawing.Size(793, 22);
+            this.mainStrip.TabIndex = 4;
+            this.mainStrip.Text = "statusStrip1";
+            // 
+            // mainStatusLabel
+            // 
+            this.mainStatusLabel.AutoSize = false;
+            this.mainStatusLabel.Name = "mainStatusLabel";
+            this.mainStatusLabel.Size = new System.Drawing.Size(778, 17);
+            this.mainStatusLabel.Spring = true;
+            this.mainStatusLabel.Text = "(there should be something here)";
+            this.mainStatusLabel.TextAlign = System.Drawing.ContentAlignment.MiddleLeft;
+            // 
+            // groupBox1
+            // 
+            this.groupBox1.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left) 
+            | System.Windows.Forms.AnchorStyles.Right)));
+            this.groupBox1.Controls.Add(this.chkGenSnapshot);
+            this.groupBox1.Controls.Add(this.chkDisableFP);
+            this.groupBox1.Controls.Add(this.chkShowTraceInfo);
+            this.groupBox1.Controls.Add(this.chkXsdValidation);
+            this.groupBox1.Controls.Add(this.btnReload);
+            this.groupBox1.Controls.Add(this.btnSettings);
+            this.groupBox1.Controls.Add(this.lblTerminologySvc);
+            this.groupBox1.Controls.Add(this.label2);
+            this.groupBox1.Controls.Add(this.lblDefinitionPath);
+            this.groupBox1.Controls.Add(this.label1);
+            this.groupBox1.Location = new System.Drawing.Point(13, 507);
+            this.groupBox1.Name = "groupBox1";
+            this.groupBox1.Size = new System.Drawing.Size(766, 129);
+            this.groupBox1.TabIndex = 1;
+            this.groupBox1.TabStop = false;
+            this.groupBox1.Text = "Settings";
+            // 
+            // chkGenSnapshot
+            // 
+            this.chkGenSnapshot.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.chkGenSnapshot.AutoSize = true;
+            this.chkGenSnapshot.Checked = global::Furore.Fhir.ValidationDemo.Properties.Settings.Default.RegenerateSnapshot;
+            this.chkGenSnapshot.DataBindings.Add(new System.Windows.Forms.Binding("Checked", global::Furore.Fhir.ValidationDemo.Properties.Settings.Default, "RegenerateSnapshot", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
+            this.chkGenSnapshot.Location = new System.Drawing.Point(418, 9);
+            this.chkGenSnapshot.Name = "chkGenSnapshot";
+            this.chkGenSnapshot.Size = new System.Drawing.Size(146, 27);
+            this.chkGenSnapshot.TabIndex = 24;
+            this.chkGenSnapshot.Text = "Regenerate snapshots";
+            this.chkGenSnapshot.UseVisualStyleBackColor = true;
+            // 
+            // chkDisableFP
+            // 
+            this.chkDisableFP.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.chkDisableFP.AutoSize = true;
+            this.chkDisableFP.Checked = global::Furore.Fhir.ValidationDemo.Properties.Settings.Default.DisableFP;
+            this.chkDisableFP.DataBindings.Add(new System.Windows.Forms.Binding("Checked", global::Furore.Fhir.ValidationDemo.Properties.Settings.Default, "DisableFP", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
+            this.chkDisableFP.Location = new System.Drawing.Point(248, 9);
+            this.chkDisableFP.Name = "chkDisableFP";
+            this.chkDisableFP.Size = new System.Drawing.Size(154, 27);
+            this.chkDisableFP.TabIndex = 23;
+            this.chkDisableFP.Text = "Disable Fhir&Path checks";
+            this.chkDisableFP.UseVisualStyleBackColor = true;
+            // 
+            // chkShowTraceInfo
+            // 
+            this.chkShowTraceInfo.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.chkShowTraceInfo.AutoSize = true;
+            this.chkShowTraceInfo.Checked = global::Furore.Fhir.ValidationDemo.Properties.Settings.Default.EnableTrace;
+            this.chkShowTraceInfo.DataBindings.Add(new System.Windows.Forms.Binding("Checked", global::Furore.Fhir.ValidationDemo.Properties.Settings.Default, "EnableTrace", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
+            this.chkShowTraceInfo.Location = new System.Drawing.Point(13, 9);
+            this.chkShowTraceInfo.Name = "chkShowTraceInfo";
+            this.chkShowTraceInfo.Size = new System.Drawing.Size(121, 27);
+            this.chkShowTraceInfo.TabIndex = 21;
+            this.chkShowTraceInfo.Text = "&Trace information";
+            this.chkShowTraceInfo.UseVisualStyleBackColor = true;
+            // 
+            // chkXsdValidation
+            // 
+            this.chkXsdValidation.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.chkXsdValidation.AutoSize = true;
+            this.chkXsdValidation.Checked = global::Furore.Fhir.ValidationDemo.Properties.Settings.Default.DoXsdValidation;
+            this.chkXsdValidation.DataBindings.Add(new System.Windows.Forms.Binding("Checked", global::Furore.Fhir.ValidationDemo.Properties.Settings.Default, "DoXsdValidation", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
+            this.chkXsdValidation.Location = new System.Drawing.Point(135, 9);
+            this.chkXsdValidation.Name = "chkXsdValidation";
+            this.chkXsdValidation.Size = new System.Drawing.Size(105, 27);
+            this.chkXsdValidation.TabIndex = 22;
+            this.chkXsdValidation.Text = "&Xsd validation";
+            this.chkXsdValidation.UseVisualStyleBackColor = true;
+            // 
+            // btnReload
+            // 
+            this.btnReload.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.btnReload.Location = new System.Drawing.Point(99, 98);
+            this.btnReload.Name = "btnReload";
+            this.btnReload.Size = new System.Drawing.Size(116, 23);
+            this.btnReload.TabIndex = 20;
+            this.btnReload.Text = "&Reload Definitions";
+            this.btnReload.UseVisualStyleBackColor = true;
+            this.btnReload.Click += new System.EventHandler(this.btnReload_Click);
+            // 
+            // btnSettings
             // 
-            this.folderBrowserDialog.Description = "Select a folder where this application can find your profiles to validate against" +
-    ".";
-            this.folderBrowserDialog.RootFolder = System.Environment.SpecialFolder.MyComputer;
-            this.folderBrowserDialog.ShowNewFolderButton = false;
+            this.btnSettings.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.btnSettings.Location = new System.Drawing.Point(12, 98);
+            this.btnSettings.Name = "btnSettings";
+            this.btnSettings.Size = new System.Drawing.Size(75, 23);
+            this.btnSettings.TabIndex = 19;
+            this.btnSettings.Text = "Change...";
+            this.btnSettings.UseVisualStyleBackColor = true;
+            this.btnSettings.Click += new System.EventHandler(this.btnSettings_Click);
+            // 
+            // lblTerminologySvc
+            // 
+            this.lblTerminologySvc.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.lblTerminologySvc.AutoSize = true;
+            this.lblTerminologySvc.Location = new System.Drawing.Point(117, 72);
+            this.lblTerminologySvc.Name = "lblTerminologySvc";
+            this.lblTerminologySvc.Size = new System.Drawing.Size(61, 13);
+            this.lblTerminologySvc.TabIndex = 18;
+            this.lblTerminologySvc.Text = "(generated)";
+            // 
+            // label2
+            // 
+            this.label2.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.label2.AutoSize = true;
+            this.label2.Location = new System.Drawing.Point(10, 72);
+            this.label2.Name = "label2";
+            this.label2.Size = new System.Drawing.Size(104, 13);
+            this.label2.TabIndex = 17;
+            this.label2.Text = "Terminology servers:";
+            // 
+            // lblDefinitionPath
+            // 
+            this.lblDefinitionPath.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.lblDefinitionPath.AutoSize = true;
+            this.lblDefinitionPath.Location = new System.Drawing.Point(117, 54);
+            this.lblDefinitionPath.Name = "lblDefinitionPath";
+            this.lblDefinitionPath.Size = new System.Drawing.Size(61, 13);
+            this.lblDefinitionPath.TabIndex = 16;
+            this.lblDefinitionPath.Text = "(generated)";
+            // 
+            // label1
+            // 
+            this.label1.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
+            this.label1.AutoSize = true;
+            this.label1.Location = new System.Drawing.Point(11, 53);
+            this.label1.Name = "label1";
+            this.label1.Size = new System.Drawing.Size(94, 13);
+            this.label1.TabIndex = 15;
+            this.label1.Text = "Path to definitions:";
+            // 
+            // openInstance
+            // 
+            this.openInstance.AddExtension = false;
+            this.openInstance.Filter = "XML|*.xml|Json|*.json";
+            this.openInstance.Title = "Open an instance";
             // 
             // MainForm
             // 
+            this.AcceptButton = this.btnValidate;
             this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
             this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
-            this.ClientSize = new System.Drawing.Size(653, 681);
-            this.Controls.Add(this.groupBox3);
-            this.Controls.Add(this.groupBox2);
+            this.ClientSize = new System.Drawing.Size(793, 678);
             this.Controls.Add(this.groupBox1);
+            this.Controls.Add(this.mainStrip);
+            this.Controls.Add(this.instanceBox);
+            this.Controls.Add(this.groupBox3);
             this.Name = "MainForm";
-            this.Text = ".NET Profile Validation Demo 1.2";
+            this.Text = ".NET Profile Validation Tool 1.4 (DSTU2)";
             this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.MainForm_FormClosed);
             this.Load += new System.EventHandler(this.MainForm_Load);
-            this.groupBox1.ResumeLayout(false);
-            this.groupBox1.PerformLayout();
-            this.groupBox2.ResumeLayout(false);
-            this.groupBox2.PerformLayout();
+            this.instanceBox.ResumeLayout(false);
             this.groupBox3.ResumeLayout(false);
             this.groupBox3.PerformLayout();
+            this.flowLayoutPanel1.ResumeLayout(false);
+            this.flowLayoutPanel1.PerformLayout();
+            this.mainStrip.ResumeLayout(false);
+            this.mainStrip.PerformLayout();
+            this.groupBox1.ResumeLayout(false);
+            this.groupBox1.PerformLayout();
             this.ResumeLayout(false);
+            this.PerformLayout();
 
         }
 
         #endregion
-
-        private System.Windows.Forms.GroupBox groupBox1;
-        private System.Windows.Forms.Label label2;
-        private System.Windows.Forms.Button btnReload;
-        private System.Windows.Forms.Button btnOpenProfileDir;
-        private System.Windows.Forms.TextBox txtProfileDirectory;
-        private System.Windows.Forms.Label label1;
-        private System.Windows.Forms.GroupBox groupBox2;
-        private System.Windows.Forms.CheckBox chkXsdValidation;
+        private System.Windows.Forms.GroupBox instanceBox;
         private System.Windows.Forms.Button btnValidate;
         private System.Windows.Forms.RichTextBox txtInstanceXml;
-        private System.Windows.Forms.CheckBox chkShowTraceInfo;
         private System.Windows.Forms.GroupBox groupBox3;
         private System.Windows.Forms.TextBox txtOutcome;
-        private System.Windows.Forms.FolderBrowserDialog folderBrowserDialog;
+        private System.Windows.Forms.StatusStrip mainStrip;
+        private System.Windows.Forms.ToolStripStatusLabel mainStatusLabel;
+        private System.Windows.Forms.GroupBox groupBox1;
+        private System.Windows.Forms.Button btnReload;
+        private System.Windows.Forms.Button btnSettings;
+        private System.Windows.Forms.Label lblTerminologySvc;
+        private System.Windows.Forms.Label label2;
+        private System.Windows.Forms.Label lblDefinitionPath;
+        private System.Windows.Forms.Label label1;
+        private System.Windows.Forms.CheckBox chkGenSnapshot;
         private System.Windows.Forms.CheckBox chkDisableFP;
+        private System.Windows.Forms.CheckBox chkShowTraceInfo;
+        private System.Windows.Forms.CheckBox chkXsdValidation;
+        private System.Windows.Forms.Button btnLoad;
+        private System.Windows.Forms.OpenFileDialog openInstance;
+        private System.Windows.Forms.Button btnCopyClipboard;
+        private System.Windows.Forms.FlowLayoutPanel flowLayoutPanel1;
+        private System.Windows.Forms.CheckBox cbErrors;
+        private System.Windows.Forms.CheckBox cbWarnings;
+        private System.Windows.Forms.CheckBox cbInformation;
     }
 }
 
diff --git a/MainForm.cs b/MainForm.cs
index 394729f..da1981c 100644
--- a/MainForm.cs
+++ b/MainForm.cs
@@ -4,11 +4,14 @@
 using Hl7.Fhir.Rest;
 using Hl7.Fhir.Serialization;
 using Hl7.Fhir.Specification.Source;
+using Hl7.Fhir.Specification.Terminology;
+using Hl7.Fhir.Support;
 using Hl7.Fhir.Utility;
 using Hl7.Fhir.Validation;
 using System;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 using System.Windows.Forms;
 
 namespace Furore.Fhir.ValidationDemo
@@ -23,92 +26,130 @@ public MainForm()
             // We create a source that takes its contents from a ZIP file (in this case the default 'specification.zip'). We decorate that source by encapsulating
             // it in a CachedResolver, which speeds up access by caching conformance resources once we got them from the large files in the ZIP.
             CoreSource = new CachedResolver(ZipSource.CreateValidationSource());
+
+            _settingsForm = new SettingsForm();
+
+            // Other initializations are done on the form_load
         }
 
-        internal IResourceResolver DirectorySource;
         internal IResourceResolver CoreSource;
-        internal IResourceResolver CombinedSource;
+        internal IResourceResolver ProfileSource;
 
+        internal ITerminologyService TerminologySource;
 
-        private void refreshProfileSource()
-        {
-            try
-            {
-                var profilePath = txtProfileDirectory.Text;
+        private SettingsForm _settingsForm;
 
-                if (!String.IsNullOrEmpty(profilePath) && Directory.Exists(profilePath))
-                {
-                    // We not only have a source for core data, we also read data from a user-specified directory. We also cache the contents of this source, like
-                    // we did with the CoreSource above.
-                    DirectorySource = new CachedResolver(new DirectorySource(profilePath, includeSubdirectories: true));
+        private void btnReload_Click(object sender, EventArgs e)
+        {
+            refreshProfileSource();
+        }
 
-                    // Finally, we combine both sources, so we will find profiles both from the core zip as well as from the directory.
-                    // By mentioning the directory source first, anything in the user directory will override what is in the core zip.
-                    CombinedSource = new MultiResolver(DirectorySource, CoreSource);
+        private void MainForm_Load(object sender, EventArgs e)
+        {
+            ProfileSource = refreshProfileSource();
+            refreshTerminologySource(ProfileSource);
 
-                }
-                else
-                    CombinedSource = CoreSource;
-            }
-            catch(Exception e)
-            {
-                MessageBox.Show($"Composing the profile source failed: {e.Message}", "Profile source");
-            }
+            ShowStatusMessage();
         }
 
-        private void txtProfileDirectory_TextChanged(object sender, EventArgs e)
+        private void MainForm_FormClosed(object sender, FormClosedEventArgs e)
         {
-            refreshProfileSource();
+            SaveSettings();
         }
 
-        private void btnReload_Click(object sender, EventArgs e)
+
+        private void SaveSettings()
         {
-            refreshProfileSource();
+            Settings.Default.Save();
         }
 
-        private void MainForm_Load(object sender, EventArgs e)
+        private OperationOutcome _lastOutcome;
+
+        private void setOutcome(OperationOutcome outcome)
         {
-            refreshProfileSource();
+            _lastOutcome = outcome;
+            refreshOutcome();
         }
 
-        private void btnOpenProfileDir_Click(object sender, EventArgs e)
+        private void refreshOutcome()
         {
-            if (!String.IsNullOrEmpty(txtProfileDirectory.Text))
-                folderBrowserDialog.SelectedPath = txtProfileDirectory.Text;
+            var outcome = _lastOutcome;
 
-            DialogResult result = folderBrowserDialog.ShowDialog();
+            if (outcome == null)
+            {
+                txtOutcome.Text = null;
+                setButtons(null, null, null);
+                return;
+            }
 
-            if (result == DialogResult.OK)
-                txtProfileDirectory.Text = folderBrowserDialog.SelectedPath;
-        }
+            var filtered = new OperationOutcome();
 
-        private void MainForm_FormClosed(object sender, FormClosedEventArgs e)
-        {
-            Settings.Default.Save();
+            foreach(var issue in outcome.Issue)
+            {
+                if (issue.Severity == OperationOutcome.IssueSeverity.Error && cbErrors.Checked == false)
+                    continue;
+                if (issue.Severity == OperationOutcome.IssueSeverity.Warning && cbWarnings.Checked == false)
+                    continue;
+                if (issue.Severity == OperationOutcome.IssueSeverity.Information && cbInformation.Checked == false)
+                    continue;
+
+                filtered.AddIssue(issue);
+            }
+
+            setButtons(outcome.Errors, outcome.Warnings, outcome.Issue.Count - outcome.Errors - outcome.Warnings);
+            var outcomeText = filtered.ToString();
+            outcomeText = outcomeText.Substring(outcomeText.IndexOf(Environment.NewLine));
+
+            if (outcome.Success)
+                outcomeText = "Overall result: SUCCESS" + outcomeText;
+            else
+                outcomeText = "Overall result: FAILURE" + outcomeText;
+
+            txtOutcome.Text = outcomeText;
+
+            void setButtons(int? errors, int? warnings, int? info)
+            {
+                cbErrors.Text = $"Errors{(errors != null ? $" ({errors})" : "")}";
+                cbWarnings.Text = $"Warnings{(warnings != null ? $" ({warnings})" : "")}";
+                cbInformation.Text = $"Information{(info != null ? $" ({info})" : "")}";
+            }
         }
 
         private void btnValidate_Click(object sender, EventArgs e)
         {
-            string output;
-
-            Settings.Default.Save();
+            setOutcome(null);
 
             if (String.IsNullOrEmpty(txtInstanceXml.Text))
             {
-                output = "Please, supply an Xml FHIR instance in the textbox above";
+                MessageBox.Show($"Please provide a FHIR instance in the {instanceBox.Text} textbox above");
+                return;
             }
-            else
+
+            if(InstanceFormat == ResourceFormat.Unknown)
+            {
+                MessageBox.Show($"The {instanceBox.Text} textbox above does not contain xml or json");
+                return;
+            }
+
+            ShowStatusMessage("Starting validation...");
+            Cursor = Cursors.WaitCursor;
+            Refresh();
+
+            try
             {
+                SaveSettings();
+
                 // Configure the validator based on the user's settings
                 // This includes a reference to the resolver that we have constructed in previous methods
                 // and which helps the validator to look for profiles
                 ValidationSettings settings = ValidationSettings.Default;
                 settings.EnableXsdValidation = chkXsdValidation.Checked;
                 settings.Trace = chkShowTraceInfo.Checked;
-                settings.ResourceResolver = this.CombinedSource;
+                settings.ResourceResolver = this.ProfileSource;
                 settings.SkipConstraintValidation = chkDisableFP.Checked;
                 settings.ResolveExteralReferences = true;
-                settings.GenerateSnapshot = true;
+                settings.GenerateSnapshot = chkGenSnapshot.Checked;
+                settings.TerminologyService = this.TerminologySource;
 
                 // This is a really cheap operation, so we can safely create a new one when we need
                 var validator = new Validator(settings);
@@ -116,21 +157,108 @@ private void btnValidate_Click(object sender, EventArgs e)
 
                 // In this case we use an XmlReader as input, but the validator has
                 // overloads for using POCO's too
-                var reader = SerializationUtil.XmlReaderFromXmlText(txtInstanceXml.Text);
-
                 Stopwatch sw = new Stopwatch();
-                sw.Start();
-                // The validator generates an OperationOutcome as output;
-                OperationOutcome result = validator.Validate(reader);
-                sw.Stop();
+                OperationOutcome result = null;
+
+                if (InstanceFormat == ResourceFormat.Xml)
+                {
+                    var reader = SerializationUtil.XmlReaderFromXmlText(txtInstanceXml.Text);
+                    sw.Start();
+                    result = validator.Validate(reader);
+                    sw.Stop();
+                }
+                else
+                {
+                    var poco = (new FhirJsonParser()).Parse<Resource>(txtInstanceXml.Text);
+                    sw.Start();
+                    result = validator.Validate(poco);
+                    sw.Stop();
+                }
 
-                output = result.ToString();
-                output += Environment.NewLine;
-                output += Environment.NewLine;
-                output += $"Validation run took {sw.ElapsedMilliseconds} miliseconds";
+                // The validator generates an OperationOutcome as output;                
+                setOutcome(result);
+                ShowStatusMessage($"Validation finished in {sw.ElapsedMilliseconds} miliseconds");
             }
+            catch (Exception ex)
+            {
+                MessageBox.Show($"{ex.GetType().Name}: {ex.Message}");
+                ShowStatusMessage("Validation failed with an exception.");
+            }
+            finally
+            {
+                Cursor = Cursors.Default;
+            }
+        }
+
+        private IResourceResolver refreshProfileSource()
+        {
+            var result = CoreSource;
 
-            txtOutcome.Text = output;
+            try
+            {
+                string profilePath = _settingsForm.ProfileDirectory;
+                setSource("Just the core specification");
+
+                if (!String.IsNullOrEmpty(profilePath))
+                {
+                    if (Directory.Exists(profilePath))
+                    {
+                        // We not only have a source for core data, we also read data from a user-specified directory. We also cache the contents of this source, like
+                        // we did with the CoreSource above.
+                        var directorySource = new CachedResolver(new DirectorySource(profilePath, includeSubdirectories: true));
+
+                        // Finally, we combine both sources, so we will find profiles both from the core zip as well as from the directory.
+                        // By mentioning the directory source first, anything in the user directory will override what is in the core zip.
+                        result = new MultiResolver(directorySource, CoreSource);
+
+                        setSource($"{profilePath} + core specification");
+                    }
+                    else
+                    {
+                        setSource($"Just the core specification, since {profilePath} does not exist", true);
+
+                    }
+                }
+            }
+            catch (Exception e)
+            {
+                MessageBox.Show($"Composing the profile source failed: {e.Message}", "Profile source");
+            }
+
+            ShowStatusMessage("Profile source was refreshed.");
+
+            return result;
+
+            void setSource(string source, bool error=false)
+            {
+                lblDefinitionPath.Text = source;
+                if (error)
+                    lblDefinitionPath.ForeColor = System.Drawing.Color.Red;
+                else
+                    lblDefinitionPath.ForeColor = Control.DefaultForeColor;
+            }
+        }
+
+        private void refreshTerminologySource(IResourceResolver resolver)
+        {
+            TerminologySource = new LocalTerminologyService(resolver);
+            setTX("Built-in terminology service");
+            var extTS = _settingsForm.TerminologyServer;
+
+            if (!String.IsNullOrEmpty(extTS))
+            {
+                TerminologySource = new ExternalTerminologyService(new FhirClient(extTS));
+                setTX($"Terminology service at {extTS}");
+
+                if (_settingsForm.UseBuiltinTx)
+                {
+                    var local = new LocalTerminologyService(resolver);
+                    TerminologySource = new FallbackTerminologyService(local, TerminologySource);
+                    setTX($"Built-in terminology service, then service at {extTS}");
+                }
+            }
+
+            void setTX(string label) => lblTerminologySvc.Text = label;
         }
 
         private void onGetExampleResource(object sender, OnResolveResourceReferenceEventArgs e)
@@ -141,7 +269,7 @@ private void onGetExampleResource(object sender, OnResolveResourceReferenceEvent
             // example directory, with the name <id>.<type>.xml, so let's try to get that file.
             ResourceIdentity reference = new ResourceIdentity(referenceToResolve);
             var filename = $"{reference.Id}.{reference.ResourceType}.xml";
-            var path = Path.Combine(txtProfileDirectory.Text, filename);
+            var path = Path.Combine(_settingsForm.ProfileDirectory, filename);
 
             if (File.Exists(path))
             {
@@ -164,6 +292,91 @@ private void onGetExampleResource(object sender, OnResolveResourceReferenceEvent
                 // Unsuccessful
                 e.Result = null;
             }
+
+        }
+
+        public void ShowStatusMessage(string message = null)
+        {
+            if (message != null)
+                mainStatusLabel.Text = $"[{DateTime.Now.ToString("t")}] {message}";
+            else
+                mainStatusLabel.Text = "Ready";
+
+            Refresh();
+        }
+
+        private void txtInstanceXml_TextChanged(object sender, EventArgs e)
+        {
+            var text = txtInstanceXml.Text;
+            if (!String.IsNullOrEmpty(text))
+            {
+                if (SerializationUtil.ProbeIsXml(text))
+                    InstanceFormat = ResourceFormat.Xml;
+                else if (SerializationUtil.ProbeIsJson(text))
+                    InstanceFormat = ResourceFormat.Json;
+                else
+                    InstanceFormat = ResourceFormat.Unknown;
+            }
+            else
+                InstanceFormat = ResourceFormat.Unknown;
+        }
+
+        private ResourceFormat _instanceFormat;
+        public Hl7.Fhir.Rest.ResourceFormat InstanceFormat
+        {
+            get => _instanceFormat;
+            set
+            {
+                _instanceFormat = value;
+                switch (_instanceFormat)
+                {
+                    case ResourceFormat.Xml:
+                        instanceBox.Text = "Instance (Xml)";
+                        break;
+                    case ResourceFormat.Json:
+                        instanceBox.Text = "Instance (Json)";
+                        break;
+                    case ResourceFormat.Unknown:
+                        instanceBox.Text = "Instance";
+                        break;
+                }
+            }
+        }
+
+        private void btnSettings_Click(object sender, EventArgs e)
+        {
+            _settingsForm.ShowDialog();
+            ProfileSource = refreshProfileSource();
+            refreshTerminologySource(ProfileSource);
+        }
+
+        private void btnLoad_Click(object sender, EventArgs e)
+        {
+            if (openInstance.ShowDialog() == DialogResult.OK)
+            {
+                try
+                {
+                    var txt = File.ReadAllText(openInstance.FileName);
+                    txtInstanceXml.Text = txt;
+                }
+                catch (Exception ex)
+                {
+                    MessageBox.Show("Open file failed: " + ex.Message);
+                }
+            }
+        }
+
+        private void btnCopyClipboard_Click(object sender, EventArgs e)
+        {
+            if(!String.IsNullOrEmpty(txtOutcome.Text))
+            {
+                System.Windows.Forms.Clipboard.SetText(txtOutcome.Text);
+            }
+        }
+
+        private void cbOutcomeFilter_CheckedChanged(object sender, EventArgs e)
+        {
+            refreshOutcome();
         }
     }
 }
diff --git a/MainForm.resx b/MainForm.resx
index b8f6272..501634a 100644
--- a/MainForm.resx
+++ b/MainForm.resx
@@ -117,7 +117,13 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
-  <metadata name="folderBrowserDialog.TrayLocation" type="System.Drawing.Point, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
-    <value>17, 17</value>
+  <metadata name="mainStrip.TrayLocation" type="System.Drawing.Point, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+    <value>290, 17</value>
+  </metadata>
+  <metadata name="openInstance.TrayLocation" type="System.Drawing.Point, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+    <value>406, 17</value>
+  </metadata>
+  <metadata name="$this.TrayHeight" type="System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
+    <value>81</value>
   </metadata>
 </root>
\ No newline at end of file
diff --git a/Properties/Settings.Designer.cs b/Properties/Settings.Designer.cs
index 5833ede..b84e171 100644
--- a/Properties/Settings.Designer.cs
+++ b/Properties/Settings.Designer.cs
@@ -12,7 +12,7 @@ namespace Furore.Fhir.ValidationDemo.Properties {
     
     
     [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
-    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.VisualStudio.Editors.SettingsDesigner.SettingsSingleFileGenerator", "14.0.0.0")]
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.VisualStudio.Editors.SettingsDesigner.SettingsSingleFileGenerator", "15.1.0.0")]
     internal sealed partial class Settings : global::System.Configuration.ApplicationSettingsBase {
         
         private static Settings defaultInstance = ((Settings)(global::System.Configuration.ApplicationSettingsBase.Synchronized(new Settings())));
@@ -46,5 +46,89 @@ public string InstanceXml {
                 this["InstanceXml"] = value;
             }
         }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("")]
+        public string TerminologyService {
+            get {
+                return ((string)(this["TerminologyService"]));
+            }
+            set {
+                this["TerminologyService"] = value;
+            }
+        }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("True")]
+        public bool UseBuiltInTX {
+            get {
+                return ((bool)(this["UseBuiltInTX"]));
+            }
+            set {
+                this["UseBuiltInTX"] = value;
+            }
+        }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("http://ontoserver.csiro.au/stu3-latest|http://tx.fhir.org/r3")]
+        public string TerminologyServiceList {
+            get {
+                return ((string)(this["TerminologyServiceList"]));
+            }
+            set {
+                this["TerminologyServiceList"] = value;
+            }
+        }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("False")]
+        public bool EnableTrace {
+            get {
+                return ((bool)(this["EnableTrace"]));
+            }
+            set {
+                this["EnableTrace"] = value;
+            }
+        }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("False")]
+        public bool DoXsdValidation {
+            get {
+                return ((bool)(this["DoXsdValidation"]));
+            }
+            set {
+                this["DoXsdValidation"] = value;
+            }
+        }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("False")]
+        public bool DisableFP {
+            get {
+                return ((bool)(this["DisableFP"]));
+            }
+            set {
+                this["DisableFP"] = value;
+            }
+        }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("False")]
+        public bool RegenerateSnapshot {
+            get {
+                return ((bool)(this["RegenerateSnapshot"]));
+            }
+            set {
+                this["RegenerateSnapshot"] = value;
+            }
+        }
     }
 }
diff --git a/Properties/Settings.settings b/Properties/Settings.settings
index 5e1368a..2148f17 100644
--- a/Properties/Settings.settings
+++ b/Properties/Settings.settings
@@ -8,5 +8,26 @@
     <Setting Name="InstanceXml" Type="System.String" Scope="User">
       <Value Profile="(Default)" />
     </Setting>
+    <Setting Name="TerminologyService" Type="System.String" Scope="User">
+      <Value Profile="(Default)" />
+    </Setting>
+    <Setting Name="UseBuiltInTX" Type="System.Boolean" Scope="User">
+      <Value Profile="(Default)">True</Value>
+    </Setting>
+    <Setting Name="TerminologyServiceList" Type="System.String" Scope="User">
+      <Value Profile="(Default)">http://ontoserver.csiro.au/stu3-latest|http://tx.fhir.org/r3</Value>
+    </Setting>
+    <Setting Name="EnableTrace" Type="System.Boolean" Scope="User">
+      <Value Profile="(Default)">False</Value>
+    </Setting>
+    <Setting Name="DoXsdValidation" Type="System.Boolean" Scope="User">
+      <Value Profile="(Default)">False</Value>
+    </Setting>
+    <Setting Name="DisableFP" Type="System.Boolean" Scope="User">
+      <Value Profile="(Default)">False</Value>
+    </Setting>
+    <Setting Name="RegenerateSnapshot" Type="System.Boolean" Scope="User">
+      <Value Profile="(Default)">False</Value>
+    </Setting>
   </Settings>
 </SettingsFile>
\ No newline at end of file
diff --git a/SettingsForm.Designer.cs b/SettingsForm.Designer.cs
new file mode 100644
index 0000000..6c6c034
--- /dev/null
+++ b/SettingsForm.Designer.cs
@@ -0,0 +1,192 @@
+namespace Furore.Fhir.ValidationDemo
+{
+    partial class SettingsForm
+    {
+        /// <summary>
+        /// Required designer variable.
+        /// </summary>
+        private System.ComponentModel.IContainer components = null;
+
+        /// <summary>
+        /// Clean up any resources being used.
+        /// </summary>
+        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing && (components != null))
+            {
+                components.Dispose();
+            }
+            base.Dispose(disposing);
+        }
+
+        #region Windows Form Designer generated code
+
+        /// <summary>
+        /// Required method for Designer support - do not modify
+        /// the contents of this method with the code editor.
+        /// </summary>
+        private void InitializeComponent()
+        {
+            this.groupBox1 = new System.Windows.Forms.GroupBox();
+            this.label2 = new System.Windows.Forms.Label();
+            this.btnOpenProfileDir = new System.Windows.Forms.Button();
+            this.txtProfileDirectory = new System.Windows.Forms.TextBox();
+            this.label1 = new System.Windows.Forms.Label();
+            this.folderBrowserDialog = new System.Windows.Forms.FolderBrowserDialog();
+            this.btnOK = new System.Windows.Forms.Button();
+            this.groupBox2 = new System.Windows.Forms.GroupBox();
+            this.cbEnableBuiltIn = new System.Windows.Forms.CheckBox();
+            this.cbxTermServers = new System.Windows.Forms.ComboBox();
+            this.groupBox1.SuspendLayout();
+            this.groupBox2.SuspendLayout();
+            this.SuspendLayout();
+            // 
+            // groupBox1
+            // 
+            this.groupBox1.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
+            | System.Windows.Forms.AnchorStyles.Right)));
+            this.groupBox1.Controls.Add(this.label2);
+            this.groupBox1.Controls.Add(this.btnOpenProfileDir);
+            this.groupBox1.Controls.Add(this.txtProfileDirectory);
+            this.groupBox1.Controls.Add(this.label1);
+            this.groupBox1.Location = new System.Drawing.Point(13, 12);
+            this.groupBox1.Name = "groupBox1";
+            this.groupBox1.Size = new System.Drawing.Size(602, 147);
+            this.groupBox1.TabIndex = 1;
+            this.groupBox1.TabStop = false;
+            this.groupBox1.Text = "Profile source directory";
+            // 
+            // label2
+            // 
+            this.label2.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
+            | System.Windows.Forms.AnchorStyles.Right)));
+            this.label2.Location = new System.Drawing.Point(6, 78);
+            this.label2.Name = "label2";
+            this.label2.Size = new System.Drawing.Size(590, 33);
+            this.label2.TabIndex = 3;
+            this.label2.Text = "For performance reasons, profiles in this directory will not be re-scanned at eac" +
+    "h validation run. Press \'Reload\' on the main screen to refresh the cached inform" +
+    "ation the validator may have.";
+            // 
+            // btnOpenProfileDir
+            // 
+            this.btnOpenProfileDir.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
+            this.btnOpenProfileDir.Location = new System.Drawing.Point(521, 39);
+            this.btnOpenProfileDir.Name = "btnOpenProfileDir";
+            this.btnOpenProfileDir.Size = new System.Drawing.Size(75, 23);
+            this.btnOpenProfileDir.TabIndex = 2;
+            this.btnOpenProfileDir.Text = "&Browse...";
+            this.btnOpenProfileDir.UseVisualStyleBackColor = true;
+            this.btnOpenProfileDir.Click += new System.EventHandler(this.btnOpenProfileDir_Click);
+            // 
+            // txtProfileDirectory
+            // 
+            this.txtProfileDirectory.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
+            | System.Windows.Forms.AnchorStyles.Right)));
+            this.txtProfileDirectory.DataBindings.Add(new System.Windows.Forms.Binding("Text", global::Furore.Fhir.ValidationDemo.Properties.Settings.Default, "ProfileSourceDirectory", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
+            this.txtProfileDirectory.Location = new System.Drawing.Point(6, 42);
+            this.txtProfileDirectory.Name = "txtProfileDirectory";
+            this.txtProfileDirectory.Size = new System.Drawing.Size(509, 20);
+            this.txtProfileDirectory.TabIndex = 1;
+            this.txtProfileDirectory.Text = global::Furore.Fhir.ValidationDemo.Properties.Settings.Default.ProfileSourceDirectory;
+            // 
+            // label1
+            // 
+            this.label1.AutoSize = true;
+            this.label1.Location = new System.Drawing.Point(6, 26);
+            this.label1.Name = "label1";
+            this.label1.Size = new System.Drawing.Size(421, 13);
+            this.label1.TabIndex = 0;
+            this.label1.Text = "The validator will look for your profiles and other conformance resources in this" +
+    " directory:";
+            // 
+            // folderBrowserDialog
+            // 
+            this.folderBrowserDialog.Description = "Select a folder where this application can find your profiles to validate against" +
+    ".";
+            this.folderBrowserDialog.RootFolder = System.Environment.SpecialFolder.MyComputer;
+            this.folderBrowserDialog.ShowNewFolderButton = false;
+            // 
+            // btnOK
+            // 
+            this.btnOK.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
+            this.btnOK.DialogResult = System.Windows.Forms.DialogResult.OK;
+            this.btnOK.Location = new System.Drawing.Point(515, 286);
+            this.btnOK.Name = "btnOK";
+            this.btnOK.Size = new System.Drawing.Size(100, 30);
+            this.btnOK.TabIndex = 2;
+            this.btnOK.Text = "OK";
+            this.btnOK.UseVisualStyleBackColor = true;
+            // 
+            // groupBox2
+            // 
+            this.groupBox2.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
+            | System.Windows.Forms.AnchorStyles.Right)));
+            this.groupBox2.Controls.Add(this.cbEnableBuiltIn);
+            this.groupBox2.Controls.Add(this.cbxTermServers);
+            this.groupBox2.Location = new System.Drawing.Point(13, 179);
+            this.groupBox2.Name = "groupBox2";
+            this.groupBox2.Size = new System.Drawing.Size(602, 88);
+            this.groupBox2.TabIndex = 4;
+            this.groupBox2.TabStop = false;
+            this.groupBox2.Text = "Terminology servers";
+            // 
+            // cbEnableBuiltIn
+            // 
+            this.cbEnableBuiltIn.AutoSize = true;
+            this.cbEnableBuiltIn.Checked = global::Furore.Fhir.ValidationDemo.Properties.Settings.Default.UseBuiltInTX;
+            this.cbEnableBuiltIn.CheckState = System.Windows.Forms.CheckState.Checked;
+            this.cbEnableBuiltIn.DataBindings.Add(new System.Windows.Forms.Binding("Checked", global::Furore.Fhir.ValidationDemo.Properties.Settings.Default, "UseBuiltInTX", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
+            this.cbEnableBuiltIn.Location = new System.Drawing.Point(9, 54);
+            this.cbEnableBuiltIn.Name = "cbEnableBuiltIn";
+            this.cbEnableBuiltIn.Size = new System.Drawing.Size(186, 17);
+            this.cbEnableBuiltIn.TabIndex = 1;
+            this.cbEnableBuiltIn.Text = "Try built-in terminology service first";
+            this.cbEnableBuiltIn.UseVisualStyleBackColor = true;
+            // 
+            // cbxTermServers
+            // 
+            this.cbxTermServers.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
+            | System.Windows.Forms.AnchorStyles.Right)));
+            this.cbxTermServers.DataBindings.Add(new System.Windows.Forms.Binding("Text", global::Furore.Fhir.ValidationDemo.Properties.Settings.Default, "TerminologyService", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
+            this.cbxTermServers.FormattingEnabled = true;
+            this.cbxTermServers.Location = new System.Drawing.Point(9, 19);
+            this.cbxTermServers.Name = "cbxTermServers";
+            this.cbxTermServers.Size = new System.Drawing.Size(578, 21);
+            this.cbxTermServers.TabIndex = 0;
+            this.cbxTermServers.Text = global::Furore.Fhir.ValidationDemo.Properties.Settings.Default.TerminologyService;
+            this.cbxTermServers.Leave += new System.EventHandler(this.cbxTermServers_Leave);
+            // 
+            // SettingsForm
+            // 
+            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
+            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
+            this.ClientSize = new System.Drawing.Size(627, 325);
+            this.Controls.Add(this.groupBox2);
+            this.Controls.Add(this.btnOK);
+            this.Controls.Add(this.groupBox1);
+            this.Name = "SettingsForm";
+            this.Text = "Change settings";
+            this.groupBox1.ResumeLayout(false);
+            this.groupBox1.PerformLayout();
+            this.groupBox2.ResumeLayout(false);
+            this.groupBox2.PerformLayout();
+            this.ResumeLayout(false);
+
+        }
+
+        #endregion
+
+        private System.Windows.Forms.GroupBox groupBox1;
+        private System.Windows.Forms.Label label2;
+        private System.Windows.Forms.Button btnOpenProfileDir;
+        private System.Windows.Forms.TextBox txtProfileDirectory;
+        private System.Windows.Forms.Label label1;
+        private System.Windows.Forms.FolderBrowserDialog folderBrowserDialog;
+        private System.Windows.Forms.Button btnOK;
+        private System.Windows.Forms.GroupBox groupBox2;
+        private System.Windows.Forms.CheckBox cbEnableBuiltIn;
+        private System.Windows.Forms.ComboBox cbxTermServers;
+    }
+}
\ No newline at end of file
diff --git a/SettingsForm.cs b/SettingsForm.cs
new file mode 100644
index 0000000..3a37a6d
--- /dev/null
+++ b/SettingsForm.cs
@@ -0,0 +1,52 @@
+using Furore.Fhir.ValidationDemo.Properties;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace Furore.Fhir.ValidationDemo
+{
+    public partial class SettingsForm : Form
+    {
+        public SettingsForm()
+        {
+            InitializeComponent();
+
+            var txServers = Settings.Default.TerminologyServiceList.Split('|').Select(s => s.Trim());
+            cbxTermServers.Items.AddRange(txServers.ToArray());
+        }
+
+        private void btnOpenProfileDir_Click(object sender, EventArgs e)
+        {
+            if (!String.IsNullOrEmpty(txtProfileDirectory.Text))
+                folderBrowserDialog.SelectedPath = txtProfileDirectory.Text;
+
+            DialogResult result = folderBrowserDialog.ShowDialog();
+
+            if (result == DialogResult.OK)
+                txtProfileDirectory.Text = folderBrowserDialog.SelectedPath;
+        }
+
+        public string ProfileDirectory => txtProfileDirectory.Text;
+
+        public string TerminologyServer => cbxTermServers.Text;
+
+        public bool UseBuiltinTx => cbEnableBuiltIn.Checked;
+
+        private void cbxTermServers_Leave(object sender, EventArgs e)
+        {
+            var newSelection = cbxTermServers.Text;
+            if (String.IsNullOrEmpty(newSelection)) return;
+
+            if (!cbxTermServers.Items.OfType<string>().Contains(newSelection))
+                cbxTermServers.Items.Add(newSelection);
+
+            Settings.Default.TerminologyServiceList = String.Join("|", cbxTermServers.Items.OfType<string>());
+        }
+    }
+}
diff --git a/SettingsForm.resx b/SettingsForm.resx
new file mode 100644
index 0000000..fae781a
--- /dev/null
+++ b/SettingsForm.resx
@@ -0,0 +1,123 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <metadata name="folderBrowserDialog.TrayLocation" type="System.Drawing.Point, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+    <value>4, 13</value>
+  </metadata>
+</root>
\ No newline at end of file
diff --git a/SyncDropBox.cmd b/SyncDropBox.cmd
new file mode 100644
index 0000000..53bec5b
--- /dev/null
+++ b/SyncDropBox.cmd
@@ -0,0 +1,3 @@
+@Echo Off
+Copy .\bin\Release\*.* \DropBox\Validator.stu3\
+Pause
diff --git a/packages.config b/packages.config
index e1fae9c..eac7bcb 100644
--- a/packages.config
+++ b/packages.config
@@ -1,4 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
+  <package id="Hl7.Fhir.Specification.DSTU2" version="0.92.5-beta3" targetFramework="net45" />
+  <package id="Hl7.Fhir.DSTU2" version="0.92.5-beta3" targetFramework="net45" />
+  <package id="Hl7.Fhir.Support" version="0.4.4-beta3" targetFramework="net45" />
+  <package id="Hl7.FhirPath" version="0.4.4-beta3" targetFramework="net45" />
   <package id="Newtonsoft.Json" version="9.0.1" targetFramework="net45" />
+  <package id="System.ValueTuple" version="4.4.0-preview2-25405-01" targetFramework="net45" />
 </packages>
\ No newline at end of file
diff --git a/specification.zip b/specification.zip
new file mode 100644
index 0000000..a10a34c
Binary files /dev/null and b/specification.zip differ