QFileDialog::getSaveFileName() does not work correctly on vista

[metow]

using :

QString filename = QFileDialog::getSaveFileName(this, tr("Save Preset"),"./presets",tr("pxml (*.pxml)"));

QString filename = QFileDialog::getSaveFileName(this, tr("Save Preset"),"./presets",tr("pxml (*.pxml)"));

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does work on windows xp well, however on vista, no lineedit, no texbox appears on the screen to input the file name, nothing. am I missing something here?