Try adding a capture phase listener to systemManager. systemManager.addEventListener(FlexEvent.HIDE, hideEventFilter, true);
private function hideEventFilter(event:FlexEvent):void { if (event.target.stage == null) event.stopImmediatePropagation(); } On 6/18/10 2:56 AM, "Stephane Guyot" <stephane.guyo...@wanadoo.fr> wrote: Alex, yes the ViewStack is newly destroyed. I use PopUpAnchor to show/hide Chart Legend, the bug is not clearly reproductible, somtimes it appears, sometimes no trouble. I'm still looking for a workaround. What should i do ? Replace PopUpAnchor and use PopUpManager ? Is it possible to plug my own FocusManager and a try/catch to hide the exception ? ViewStack, CheckBox and this morning I've got a new version with Group : TypeError: Error #1009: Il est impossible d'accéder à la propriété ou à la méthode d'une référence d'objet nul. at mx.managers::FocusManager/childHideHandler()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\FocusManager.as:1759] at flash.events::EventDispatcher/dispatchEventFunction() at flash.events::EventDispatcher/dispatchEvent() at mx.core::UIComponent/dispatchEvent()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:12528] at mx.core::UIComponent/setVisible()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:3088] at mx.core::UIComponent/set visible()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:3047] at spark.components.supportClasses::ScrollerLayout/set hsbVisible()[E:\dev\4.x\frameworks\projects\spark\src\spark\components\supportClasses\ScrollerLayout.as:105] at spark.components.supportClasses::ScrollerLayout/updateDisplayList()[E:\dev\4.x\frameworks\projects\spark\src\spark\components\supportClasses\ScrollerLayout.as:429] at spark.components.supportClasses::GroupBase/updateDisplayList()[E:\dev\4.x\frameworks\projects\spark\src\spark\components\supportClasses\GroupBase.as:1224] at spark.components::Group/updateDisplayList()[E:\dev\4.x\frameworks\projects\spark\src\spark\components\Group.as:899] at spark.skins::SparkSkin/updateDisplayList()[E:\dev\4.x\frameworks\projects\spark\src\spark\skins\SparkSkin.as:191] at mx.core::UIComponent/validateDisplayList()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:8709] at mx.managers::LayoutManager/validateDisplayList()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:663] at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:736] at mx.managers::LayoutManager/doPhasedInstantiationCallback()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:1072] at flash.utils::Timer/_timerDispatch() at flash.utils::Timer/tick() Stephane Just do it : http://www.kiva.org/lender/stephane4127 Le 16 juin 2010 à 18:32, Alex Harui a écrit : This indicates that the viewstack is not on stage. Is it being newly created or destroyed? On 6/16/10 1:02 AM, "Stephane Guyot" <stephane.guyo...@wanadoo.fr <x-msg://825/stephane.guyo...@wanadoo.fr> > wrote: Hi list, working with Flex 4, I'm looking for a workaround for a very annoying bug : http://bugs.adobe.com/jira/browse/SDK-26273 TypeError: Error #1009: Il est impossible d'accéder à la propriété ou à la méthode d'une référence d'objet nul. at mx.managers::FocusManager/childHideHandler()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\FocusManager.as:1759] at flash.events::EventDispatcher/dispatchEventFunction() at flash.events::EventDispatcher/dispatchEvent() at mx.core::UIComponent/dispatchEvent()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:12528] at mx.core::UIComponent/setVisible()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:3088] at mx.containers::ViewStack/commitSelectedIndex()[E:\dev\4.x\frameworks\projects\framework\src\mx\containers\ViewStack.as:1201] Sometimes the bug appears for ViewStack, CheckBox .... working with Flex charting components I'm in a hybrid world, spark and halo .... Any suggestions are wellcome, Stephane Just do it : http://www.kiva.org/lender/stephane4127 -- Alex Harui Flex SDK Team Adobe System, Inc. http://blogs.adobe.com/aharui