Add dialog to edit timeout duration

src/NoDoz/FormDurationEdit.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Windows.Forms;
+using NodaTime;
+
+namespace NoDoz
+{
+    public partial class FormDurationEdit : Form
+    {
+        public FormDurationEdit()
+        {
+            InitializeComponent();
+        }
+
+        public Duration? Timeout { get; private set; }
+
+        private void buttonCancel_Click(object sender, EventArgs e) => DialogResult = DialogResult.Cancel;
+
+        private void buttonDone_Click(object sender, EventArgs e)
+        {
+            DialogResult = DialogResult.OK;
+
+            if (!checkBoxIndefinite.Checked)
+                Timeout = Duration.FromTimeSpan(new TimeSpan((int)numericUpDownHours.Value, (int)numericUpDownMinutes.Value, (int)numericUpDownSeconds.Value));
+        }
+
+        private void numericUpDownHours_Enter(object sender, EventArgs e) => numericUpDownHours.Select(0, 10);
+
+        private void numericUpDownMinutes_Enter(object sender, EventArgs e) => numericUpDownMinutes.Select(0, 10);
+
+        private void numericUpDownSeconds_Enter(object sender, EventArgs e) => numericUpDownSeconds.Select(0, 10);
+
+        private void checkBoxIndefinite_CheckedChanged(object sender, EventArgs e)
+        {
+            numericUpDownHours.Enabled = !checkBoxIndefinite.Checked;
+            numericUpDownMinutes.Enabled = !checkBoxIndefinite.Checked;
+            numericUpDownSeconds.Enabled = !checkBoxIndefinite.Checked;
+        }
+
+        private void FormDurationEdit_KeyUp(object sender, KeyEventArgs e)
+        {
+            if (e.KeyCode == Keys.Escape)
+            {
+                DialogResult = DialogResult.Cancel;
+                e.Handled = true;
+                e.SuppressKeyPress = true;
+            }
+        }
+    }
+}