QFontDialog doesn't always open

Something changed from 4.6.2 to 4.6.3 in how the QFontDialog works.

In 4.6.3, the following code does not work reliably in my application (the dialog does not open):

m_font_dialog = new QFontDialog();
m_font_dialog->setOption(QFontDialog::DontUseNativeDialog, true);
m_font_dialog->setOption(QFontDialog::NoButtons, true);
m_font_dialog->show();

Replacing the 4.6.3 libraries with 4.6.2 libraries makes things work perfectly.

I'm still working on providing a test case project for this bug, but I thought I'd submit it now in case anyone else is having a similar issue.