FocusManager Generates Error

Get this error when trying to close a Tree Component in PopUpAnchor Control.

TypeError: Error #1009: Cannot access a property or method of a null  object reference.

    at  mx.managers::FocusManager/childHideHandler()[E:\dev\4.0.0\frameworks\ projects\framework\src\mx\managers\FocusManager.as:1744]

     at flash.events::EventDispatcher/dispatchEventFunction()

    at  flash.events::EventDispatcher/dispatchEvent()

    at  mx.core::UIComponent/dispatchEvent()[E:\dev\4.0.0\frameworks\projects \framework\src\mx\core\UIComponent.as:12269]

     at  mx.core::UIComponent/setVisible()[E:\dev\4.0.0\frameworks\projects\fr amework\src\mx\core\UIComponent.as:3038]

     at mx.core::UIComponent/set  visible()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\core\UICo mponent.as:2997]

     at  mx.controls::Button/http://www.adobe.com/2006/flex/mx/internal::viewSkinForPhase()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\controls\Button.a s:1953]

     at  mx.controls::PopUpButton/http://www.adobe.com/2006/flex/mx/internal::viewSkin()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\controls\PopUpBut ton.as:712]

     at  mx.controls::Button/updateDisplayList()[E:\dev\4.0.0\frameworks\proje cts\framework\src\mx\controls\Button.as:1754]

     at  mx.core::UIComponent/validateDisplayList()[E:\dev\4.0.0\frameworks\pr ojects\framework\src\mx\core\UIComponent.as:8531]

     at  mx.managers::LayoutManager/validateDisplayList()[E:\dev\4.0.0\framewo rks\projects\framework\src\mx\managers\LayoutManager.as:663]

     at  mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.0.0\frame works\projects\framework\src\mx\managers\LayoutManager.as:736]

     at  mx.managers::LayoutManager/doPhasedInstantiationCallback()[E:\dev\4.0 .0\frameworks\projects\framework\src\mx\managers\LayoutManager.as:1072 ]

Issue Description :

               

                 I have got the same exception. I have a PopUpAnchor that contains a Tree Component with a custom itemRenderer. Itemrenderer has checkbox when i check the sum of the checkboxes and Then Close the PopUpAnchor i get the above issue

Solution : This issue is with Adobe SDK.

                I put for every checkbox the property focusEnabled=false and I don't get any error