Foo extends ListBase bug !!! Serious !!!

Question

hi, listbase changed in sdk build 19786,
19786 + post like not released 20135 which is included in the prerelease flashbuilder
override protected function partAdded(partName:String, instance:Object):void
        super.partAdded(partName, instance);
        if (instance == dataGroup)
            // Not your typical delegation, see 'set useVirtualLayout'
            if (_useVirtualLayout && dataGroup.layout && dataGroup.layout.virtualLayoutSupported)
                dataGroup.layout.useVirtualLayout = true;
            dataGroup.addEventListener(
                RendererExistenceEvent.RENDERER_ADD, dataGroup_rendererAddHandler);
            dataGroup.addEventListener(
                RendererExistenceEvent.RENDERER_REMOVE, dataGroup_rendererRemoveHandler);
so, on  RendererExistenceEvent.RENDERER_ADD and REMOVE the handler functions are called.
Previously to that version eg. in
there is no internal handling when a item is added to the datagroup.
pre 19786
override protected function partAdded(partName:String, instance:Object):void
        super.partAdded(partName, instance);
        if (instance == dataGroup)
            // Not your typical delegation, see 'set useVirtualLayout'
            if (_useVirtualLayout && dataGroup.layout)
                dataGroup.layout.useVirtualLayout = true;
Some libs exists eg. the expander Toolkit or a Flex 4 Tabbar http://examples.flashdan.net/blog/posts/Flex%204%20TabBar/srcview/inde x.html
that  rely on the RendererExistenceEvent.RENDERER_ADD,  RendererExistenceEvent.RENDERER_REMOVE Event to trigger a different  behaviour.
In the above tabbar CustomTabBar Class which extends TabBar extends TabbarBase extends ListBase;  the following partAdded method is included:
It runs greate in pre versions of sdk 19786 but breaks completly in 19786!!!
Custom tabbar part added:
protected override function partAdded(partName:String, instance:Object):void {
            super.partAdded(partName, instance);
            if(instance == dataGroup){
                dataGroup.addEventListener(RendererExistenceEvent.RENDERER_ADD, dataGroup_rendererAddHandler);
                dataGroup.addEventListener(RendererExistenceEvent.RENDERER_REMOVE, dataGroup_rendererRemoveHandler);
                dataGroup.addEventListener(CustomTabBarCloseEvent.CLOSE_TAB, closeHandler);

Answer 1

Could you just remove these lines from your partAdded?
dataGroup.addEventListener(RendererExistenceEvent.RENDERER_ADD, dataGroup_rendererAddHandler);
dataGroup.addEventListener(RendererExistenceEvent.RENDERER_REMOVE, dataGroup_rendererRemoveHandler);