Details
Description
QSystemTrayIcon may not be recreated after Explorer crash/restart due to WM_TASKBARCREATED being blocked by UIPI
Steps to reproduce / test case
1) Launch a Qt application elevated (as administrator) with UAC enabled. (in this case Explorer is a medium privilege process, the application is high privilege).
2) Kill and restart Windows Explorer using the Task Manager
3) Any QSystemTrayIcon the application may have will not recreate, as the WM_TASKBARCREATED is being blocked by UIPI (medium -> high process)
More information
The WM_TASKBARCREATED must be explicitly allowed through the message filter with ChangeWindowMessageFilter
A proposed fix is available as http://qt.gitorious.org/qt/qt/merge_requests/1110