QFileDialog - will be closed after selecting a file

[skyperhh]

Hello,

on Linux, Qt 4.5.2, i open a QFileDialog, select a file and at once the dialog will be closed.
No crash, get filename(s) as return value, it's equal if its a static or "normal" qfiledialog.
My problem, i added a preview to the filedialog and can't use it, because the dialog will be closed after select a file. Maybe a bug, because it's on my subclass and at the normal QFileDialog class ?

QFileDialog box;
QStringList fileNames;
box.setFileMode(QFileDialog::ExistingFile);
if (box.exec())
    fileNames = box.selectedFiles();

QFileDialog box;
QStringList fileNames;
box.setFileMode(QFileDialog::ExistingFile);
if (box.exec())
    fileNames = box.selectedFiles();

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Thank you

Bo