Moving the non-floating QToolBar crashes application

It even works on new applications without any user code;
If you create an application on a form template MainWindov, then change the property of the QToolBar "floatable" on a false, the toolbar when moving will magnetic join to the resolved edges of a window. If the window is maximized and the toolbar was given a far from the edge to which it will move when you release it, and until a toolbar "flying" to the edge of the window, double-or triple-click, it will lead to a crash of the application.
Sorry for my english, it's not so good, but if you dont understand, I can write a bug in the video and upload to youtube. This bug can be traced not only on my computer, but also with other windows 7. On other platforms, unfortunately, I have no possibility to check it.

UPD (4.04.2012 4:45AM):
Check on Linux Mint x32. Application crashed.