Qt application does not terminate when QFileDialog is used

(this is the same problem posted here:
http://qt-project.org/forums/viewthread/34619/
I'm attaching a simple project that shows this problem)

I’m experiencing a weird behavior in Qt.

I have a Qt project in windows where as soon as I use
QFileDialog::getOpenFileNames
then, exit the application, it turns out that the process keeps running as a task.
This problem only occurs when I use Qt5.1.X-32bit in my 64bit PC.

Everything works perfectly in Qt5.1.X-64 bit.

I’ve tried to reinstall microsoft redistributable without success. I have VS2010 SP1. (I’m using VS2010 for 32 bit and VS2012 for 64 bit)

I’ve also tried to call:
QApplication::exit(0);
but the application process does not stop.

This is the stack once I exit the application and pause the debugger:
@
0 NtWaitForMultipleObjects ntdll32 0x7731015d
1 WaitForMultipleObjectsEx KERNELBASE 0x750a15e9
2 WaitForMultipleObjectsExImplementation kernel32 0x76bf19fc
3 RealMsgWaitForMultipleObjectsEx USER32 0x7533086a
4 CCliModalLoop::BlockFn callctrl.cxx 1222 0x76402bf1
...
@

Does anyone know where this error comes from?
Is this a bug?

Thank you very much!