From deca6799b804e682682a457d6cf033e57f8bb9ab Mon Sep 17 00:00:00 2001
From: Lars Brubaker <larsbrubaker@gmail.com>
Date: Tue, 16 Nov 2021 10:41:23 -0800
Subject: [PATCH] Fix crash when ui refreshes during async opperation

---
 MatterControlLib/PartPreviewWindow/Object3DTreeBuilder.cs | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/MatterControlLib/PartPreviewWindow/Object3DTreeBuilder.cs b/MatterControlLib/PartPreviewWindow/Object3DTreeBuilder.cs
index 4ac2fb01e..002fcd123 100644
--- a/MatterControlLib/PartPreviewWindow/Object3DTreeBuilder.cs
+++ b/MatterControlLib/PartPreviewWindow/Object3DTreeBuilder.cs
@@ -119,12 +119,8 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 				PointSize = theme.DefaultFontSize,
 			};
 
-			if (keyValues.ContainsKey(item))
+			if (!keyValues.ContainsKey(item))
 			{
-				throw new Exception("Duplcate item entry");
-			}
-			else
-			{ 
 				keyValues.Add(item, node);
 			}