QFileDialog::getSaveFileName hangs under gnome when calls gtk2 save dialog

Under KDE it works correct (kde save dialog) , but under gnome gtk2 dialog hangs for 10-30 seconds, after that it shows dialog, but when try to change dir, again hangs 10-15 secs until dir is changed.
Hang occurs ONLY if dir parameter is passed. If it's empty then everything looks ok.
Simple call could be:
QString fileName = QFileDialog::getSaveFileName(this, "Test", dir.absolutePath(), NULL, NULL, 0);