Disable selection on children to ensure Click event on widget

- MatterHackers/MCCentral#2779
New Cut/Copy/Paste/Save menu items intermittently function

PartPreviewWindow/PopupMenu.cs

@@ -96,6 +96,8 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 				content = textWidget;
 			}
 
+			content.Selectable = false;
+
 			var menuItem = new MenuItem(content, theme)
 			{
 				Name = name + " Menu Item",

PartPreviewWindow/View3D/View3DWidget.cs

@@ -395,8 +395,6 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 						}
 						break;
 
-
-
 					case Keys.Delete:
 					case Keys.Back:
 						scene.DeleteSelection();

PartPreviewWindow/ViewControls3D.cs

@@ -30,6 +30,7 @@ either expressed or implied, of the FreeBSD Project.
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
@@ -607,7 +608,7 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 				{
 					Title = "Cut".Localize(),
 					Shortcut = "Ctrl+X",
-					Action = async () =>
+					Action = () =>
 					{
 						sceneContext.Scene.Cut();
 					},
@@ -617,7 +618,7 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 				{
 					Title = "Copy".Localize(),
 					Shortcut = "Ctrl+C",
-					Action = async () =>
+					Action = () =>
 					{
 						sceneContext.Scene.Copy();
 					},
@@ -627,7 +628,7 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 				{
 					Title = "Paste".Localize(),
 					Shortcut = "Ctrl+V",
-					Action = async () =>
+					Action = () =>
 					{
 						sceneContext.Scene.Paste();
 					},