RC3: Copy and Paste really slow

function levelBuilderPaste(%val)
{
   if (%val)
   {
      %undo = new UndoScriptAction() { actionName = "Paste"; class = UndoPasteAction; };
      %undo.objectList = new SimSet();
      // When we make the switch to fileObject.writeObject for loading and saving, this
      // will be much nicer.
      %objectList = $currentSceneGraph.getSceneObjectList();
      addToLevelCallback($levelBuilderClipboardFile);
      %newObjectList = $currentSceneGraph.getSceneObjectList();
      
      // Anything in the new list but not in the old list was just added.
      for (%i = 0; %i < getWordCount(%newObjectList); %i++)
      {
         %obj = getWord(%newObjectList, %i);
         %found = false;
         for (%j = 0; %j < getWordCount(%objectList); %j++)
         {
            if (getWord(%objectList, %j) == %obj)
               %found = true;
         }
         
         if (!%found)
            %undo.objectList.add(%obj);
      }
      
      if (%undo.objectList.getCount() > 0)
         %undo.addToManager(LevelBuilderUndoManager);
   }
}