System Tray Icon Example doesn't quit on system reboot/shutdown on Windows XP when main window is minimized

On windows XP (tested on four diffrent computer with SP2 or SP3) I have application which use QSystemTrayIcon. Main windows minimize to tray icon instead of close. When I have main windows minimized and click reboot or shutdown other programs start closing but my app won't.

I found this problem in my application and after few days of searching I find the some problem in SysTray example from QT 5.2.0.
(5.2.0\msvc2010\examples\widgets\desktop\systray)

Steps to reproduce:
1. Compile SysTray example & run systray.exe
2. Click close ("X" in upper right corner of window)
3. Try to reboot/shutdown system
4. Nothing happend.

This problem doesn't occur on windows 7 & 8.
I also check that with Qt 5.0 dll's there is no problem.

I found that until I don't call trayIcon->show() everything is fine.
I create whole trayIcon object set all properties etc., run application and system shutdown properly. When I call trayIcon->show(); it doesn't shutting down.

The problem is really important becouse there is still a lot of people which use XP.