Fix UI text no longer renders over everything:

- Fix UI text no longer renders over everything without having to enter Play mode

Suggested by ScruffyRuffles

Author: hai-vr

Assets/Hai/LightboxViewer/Scripts/Editor/LightboxViewerEditorWindow.cs

@@ -287,6 +287,11 @@ private void Enable()
             ProjectRenderQueue.LoadLightbox(lightboxScene);
             _enabled = true;
             Realign();
+
+            // Fix UI text rendering over everything.
+            // This normally fixes itself when entering Play mode, but this will allow not needing to enter Play mode.
+            var LessEqual = 4;
+            Shader.SetGlobalInt("unity_GUIZTestMode", LessEqual);
         }
 
         private void Realign()