disabling code completion in the options menu now works for the code editor

see SD-1763

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CodeCompletionEditorAdapter.cs

@@ -31,6 +31,10 @@ namespace ICSharpCode.AvalonEdit.AddIn
 		{
 			if (data == null || !data.Items.Any())
 				return null;
+			if(CodeCompletionOptions.EnableCodeCompletion == false)
+			{
+				return null;
+			}
 			SharpDevelopCompletionWindow window = new SharpDevelopCompletionWindow(this, this.TextEditor.TextArea, data);
 			textEditor.ShowCompletionWindow(window);
 			return window;

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/SharpDevelopCompletionWindow.cs

@@ -70,6 +70,11 @@ namespace ICSharpCode.AvalonEdit.AddIn
 			if (itemList == null)
 				throw new ArgumentNullException("itemList");
 			
+			if(CodeCompletionOptions.EnableCodeCompletion == false)
+			{
+				throw new InvalidOperationException("trying to construct SharpDevelopCompletionWindow while EnableCodeCompletion = false");
+			}
+			
 			if (!itemList.ContainsAllAvailableItems) {
 				// If more items are available (Ctrl+Space wasn't pressed), show this hint
 				this.EmptyText = StringParser.Parse("${res:ICSharpCode.AvalonEdit.AddIn.SharpDevelopCompletionWindow.EmptyText}");