Merge pull request #3030 from StephenHodgson/vNEXT-PlayModeSpeedup

Helped speed up play mode transition.

Author: StephenHodgson

Assets/MixedRealityToolkit/_Core/Utilities/Editor/Setup/.MixedRealityEditorSettings.cs

@@ -46,13 +46,13 @@ public static string MixedRealityToolkit_RelativeFolderPath
 
         static MixedRealityEditorSettings()
         {
-            SetIconTheme();
-
-            if (!IsNewSession)
+            if (!IsNewSession || Application.isPlaying)
             {
                 return;
             }
 
+            SetIconTheme();
+
             bool refresh = false;
             bool restart = false;