 import mx.styles.IStyleClient;
 import mx.styles.StyleProtoChain;
 
+import spark.components.supportClasses.DisplayPlane;
 import spark.components.supportClasses.GroupBase;
 import spark.core.DisplayObjectSharingMode;
 import spark.core.IGraphicElement;
 import spark.core.ISharedDisplayObject;
+import spark.events.DisplayPlaneObjectExistenceEvent;
 import spark.events.ElementExistenceEvent;
-import spark.components.supportClasses.TextBase;
 import spark.primitives.shaders.ColorBurnShader;
 import spark.primitives.shaders.ColorDodgeShader;
 import spark.primitives.shaders.ColorShader;

     */ 
    private function addDisplayObjectToDisplayList(child:DisplayObject, index:int = -1):void
    {
        if (child.parent == this)
            super.setChildIndex(child, index != -1 ? index : super.numChildren - 1);
        else
            super.addChildAt(child, index != -1 ? index : super.numChildren);
    }

    /**

        
            if (isValidScaleGrid())
            {
				// FIXME (egeorgie): how about overlays in this case? Should we care about those?
                if (numChildren > 0)
                    throw new Error(resourceManager.getString("components", "scaleGridGroupError"));

