Segmentation fault when widget is garbage collected

This example program uses the QuiLoader class similar to how it is used by the QtPy abstraction layer.

Running the application using the command:

python -X dev -m crash

the application can be made to crash (most of the time) by either:

• opening the dialog and after making sure the calendar popup is shown, closing the dialog and waiting for a bit; or
• opening the dialog and closing it without triggering the calendar popup, and doing this more than once.

Running with:

QT_LOGGING_RULES=qt.qpa.backingstore.debug=true;qt.qpa.backingstore.info=true

shows that the dialog is not immediately deleted / garbage collected after the dialog variable goes out of scope.

I have no idea if my usage of Qt for Python is incorrect, or if this is a PySde6 bug, or both...