have you any solutions from this yet?
I am having the same problem when i am making changes in views.
In my case, I wasn't using visual states to make state transitions however
through dynamically adding and removing elements.
null reference error with the following msg:
at spark.components::Scroller/focusInHandler()at
spark.components::Scroller/focusInHandler()[E:\dev\4.5.1\frameworks\projects\spark\src\spark\components\Scroller.as:1273]
at flash.display::Stage/set focus()
at
mx.core::UIComponent/setFocus()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\core\UIComponent.as:9895]
at
mx.managers::FocusManager/setFocus()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\managers\FocusManager.as:598]
at
mx.managers::FocusManager/activate()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\managers\FocusManager.as:864]
at
mx.managers.systemClasses::ActiveWindowManager/deactivateForm()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\managers\systemClasses\ActiveWindowManager.as:259]
at
mx.managers.systemClasses::ActiveWindowManager/deactivate()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\managers\systemClasses\ActiveWindowManager.as:213]
at
mx.managers::FocusManager/hideHandler()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\managers\FocusManager.as:1765]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at
mx.core::UIComponent/dispatchEvent()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\core\UIComponent.as:13128]
at
mx.controls::Menu/dispatchEvent()[E:\dev\4.5.1\frameworks\projects\mx\src\mx\controls\Menu.as:1528]
at
mx.core::UIComponent/setVisible()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\core\UIComponent.as:3280]
at mx.core::UIComponent/set
visible()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\core\UIComponent.as:3238]
at
mx.controls::Menu/hide()[E:\dev\4.5.1\frameworks\projects\mx\src\mx\controls\Menu.as:1773]
at
mx.controls::Menu/http://www.adobe.com/2006/flex/mx/internal::hideAllMenus()[E:\dev\4.5.1\frameworks\projects\mx\src\mx\controls\Menu.as:2528]
at
mx.controls::Menu/mouseUpHandler()[E:\dev\4.5.1\frameworks\projects\mx\src\mx\controls\Menu.as:1928]
