Fix bad performance of OpenDialog caused by explicit call to Layout

Author: tznind

src/UI/Editor.cs

@@ -1270,10 +1270,9 @@ private void Open()
         var ofd = new OpenDialog()
         {
             Title = "Open",
-//            AllowedTypes = new List<IAllowedType>(new[] { new AllowedType("View", SourceCodeFile.ExpectedExtension) })
+            AllowedTypes = new List<IAllowedType>(new[] { new AllowedType("View", SourceCodeFile.ExpectedExtension) })
         };
-        ofd.Layout();
-
+        
         app.Run(ofd, this.ErrorHandler);
 
         if (!ofd.Canceled)