Due to windows-specific problems, the application does not properly terminate when the dialog is parented to a foreign window.
We work around this by terminating manually when the dialog closes.

This seems to fall in the category of

Changing transient parents generally does not really work on Windows; no guarantees can be given for foreign windows.

(https://bugreports.qt.io/browse/QTBUG-55669)

Fixes T7240

Install patch, check whether config can be opened and closed multiple times