If there is an idle timer (QTimer::start(0)) running in the main loop of a Qt program, trying to pop up a file open dialog (QFileDialog::getOpenFileName()) produces an empty dialog (no buttons). If the timeout of the timer is not 0, the problem doesn't occur ( even with timeout = 1 ). There is a similar problem with QFileDialog::getSaveFileName(), but not with other generic dialogs such as QColorDialog. See the attached example to reproduce the bug.