Steps to reproduce:

• Remove settings file of mdi/application example ( ~/.config/QtProject/Application Example.conf )
• Launch example

I didn't record the complete error information, because after comment error line (happened on line 206) was successfully run for the first time, it can't be repeated again.

```

205    geometry = settings.value('geometry', QByteArray)
206    if geometry.size():
207        self.restoreGeometry(geometry)

```

The simple error message is as follows：

`descriptor 'size' of 'PySide6.QtCore.QByteArray' object needs an argument`