I'm not using 4.5.1 yet, so this observation is more "generic" than you may want. When using the tabnavigator without states, but just setting the index, I get this error if I try to access a variable/method in any child other than the first child. Apparently they are not created until they are displayed the first time. A possible solution is to display each one briefly in a loop at startup. Perhaps you could even make the container invisible so it's faster - not sure.
Hope this helps, Fred. From: flexcoders@yahoogroups.com [mailto:flexcoders@yahoogroups.com] On Behalf Of yms0411 Sent: Sunday, December 25, 2011 1:52 AM To: flexcoders@yahoogroups.com Subject: [flexcoders] Re: Problem migrating project from FB 4.5 to FB 4.5.1 - runtime error 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\proj ects\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\framewo rk\src\mx\core\UIComponent.as:9895] at mx.managers::FocusManager/setFocus()[E:\dev\4.5.1\frameworks\projects\fr amework\src\mx\managers\FocusManager.as:598] at mx.managers::FocusManager/activate()[E:\dev\4.5.1\frameworks\projects\fr amework\src\mx\managers\FocusManager.as:864] at mx.managers.systemClasses::ActiveWindowManager/deactivateForm()[E:\dev\4 .5.1\frameworks\projects\framework\src\mx\managers\systemClasses\ActiveW indowManager.as:259] at mx.managers.systemClasses::ActiveWindowManager/deactivate()[E:\dev\4.5.1 \frameworks\projects\framework\src\mx\managers\systemClasses\ActiveWindo wManager.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\fr amework\src\mx\core\UIComponent.as:13128] at mx.controls::Menu/dispatchEvent()[E:\dev\4.5.1\frameworks\projects\mx\sr c\mx\controls\Menu.as:1528] at mx.core::UIComponent/setVisible()[E:\dev\4.5.1\frameworks\projects\frame work\src\mx\core\UIComponent.as:3280] at mx.core::UIComponent/set visible()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\core\UICompo nent.as:3238] at mx.controls::Menu/hide()[E:\dev\4.5.1\frameworks\projects\mx\src\mx\cont rols\Menu.as:1773] at mx.controls::Menu/http://www.adobe.com/2006/flex/mx/internal::hideAllMen us()[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\s rc\mx\controls\Menu.as:1928]
