MainWindow.xaml

<Window x:Class="RimXML.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:ae="http://icsharpcode.net/sharpdevelop/avalonedit"
        xmlns:local="clr-namespace:RimXML"
        mc:Ignorable="d"
        Title="RimXML" Height="450" Width="800">
    <DockPanel>
        <Menu DockPanel.Dock="Top">
            <MenuItem Header="_File">
                <MenuItem Name="BtnNew" Header="_New"/>
                <MenuItem Name="BtnOpen" Header="_Open"/>
                <MenuItem Name="BtnSave" Header="_Save"/>
                <MenuItem Name="BtnSaveAs" Header="S_ave As.."/>
            </MenuItem>
            <MenuItem Header="_Options">
                <MenuItem Name="BtnLocateRimworld" Header="_Locate Rimworld" Click="BtnLocateRimworld_Click"/>
                <MenuItem Name="BtnPreferences" Header="_Preferences"/>
            </MenuItem>
            <MenuItem Name="MenuItemDefTypes" Header="Def Types"/>
        </Menu>
        <ae:TextEditor Name="Editor" SyntaxHighlighting="XML" ShowLineNumbers="True" PreviewTextInput="Editor_TextInput" />
    </DockPanel>
</Window>