diff --git a/MatterControlLib/Library/Providers/LibraryConfig.cs b/MatterControlLib/Library/Providers/LibraryConfig.cs
index 21b4351eae..5a50bb15fa 100644
--- a/MatterControlLib/Library/Providers/LibraryConfig.cs
+++ b/MatterControlLib/Library/Providers/LibraryConfig.cs
@@ -224,7 +224,11 @@ async void setItemThumbnail(ImageBuffer icon)
 					{
 						setItemThumbnail(image);
 					}));
-					thumbnailListener?.Invoke(icon);
+					// Invoke callback on UI thread to ensure Invalidate() works correctly
+					UiThread.RunOnIdle(() =>
+					{
+						thumbnailListener?.Invoke(icon);
+					});
 				}
 			}
 
diff --git a/Submodules/agg-sharp b/Submodules/agg-sharp
index 2f0d725538..86b43fd458 160000
--- a/Submodules/agg-sharp
+++ b/Submodules/agg-sharp
@@ -1 +1 @@
-Subproject commit 2f0d725538c880d740ed516d6eb9d3d261f68c58
+Subproject commit 86b43fd458c3cf470f517d1a3c5383a9851de2cb