[Cocoa] QDialogs with WindowStayOnStopHint parent

Under Cocoa, if you open a QDialog(QFileDialog, QfontDialog tested) and put as a parent a window that has the Qt::WindowStayOnStopHint flag, then the QDialog will open under the parent window and there is no way to make it go in front.

This is really bad because when you have a fullscreen window with the stay on top flag, there is no way to know that a QDialog is opened.

I happens with all qt versions i have tested (4.5.1, 4.6, 4.6.2, 4.7.0 preview) but only with cocoa. It works perfectly under carbon.