Pulled latest changes

EditTextBox.cs

@@ -56,12 +56,12 @@ protected override void OnLostKeyboardFocus(KeyboardFocusChangedEventArgs e)
 			}
 		}
 
-		bool commiting;
+		bool committing;
 
 		void Commit()
 		{
-			if (!commiting) {
-				commiting = true;
+			if (!committing) {
+				committing = true;
 
 				if (Node != null) {
 					Node.IsEditing = false;
@@ -79,7 +79,7 @@ void Commit()
 				//    Init();
 				//}
 
-				commiting = false;
+				committing = false;
 			}
 		}
 	}

LinesRenderer.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Text;
 using System.Windows;
@@ -27,6 +28,13 @@ SharpTreeNodeView NodeView
 
 		protected override void OnRender(DrawingContext dc)
 		{
+			if (NodeView.Node == null) {
+				// This seems to happen sometimes with DataContext==DisconnectedItem,
+				// though I'm not sure why WPF would call OnRender() on a disconnected node
+				Debug.WriteLine($"LinesRenderer.OnRender() called with DataContext={NodeView.DataContext}");
+				return;
+			}
+
 			var indent = NodeView.CalculateIndent(NodeView.Node);
 			var p = new Point(indent + 4.5, 0);