QApplication has special treatment through the extra rules of only one QApplication instance may exist. To ensure this, different approaches were used. The first attempt was using refcounts and made sure that "del qApp" really destroys the QApplication instance. This did not work in interactive mode because the automatic underscore variable creates cycles. As a simple workaround, we assigned None to underscore when a QApplication was created. When moving to the new concept of an explicit shutdown() call, this assignment was forgotten to remove. [ChangeLog][PySide6] A left-over replacement of the interactive underscore variable when QApplication is created was removed. Change-Id: I78f3e3714531d599c4b5b76f956b1d631014ad94 Pick-to: 6.2 Fixes: PYSIDE-1758 Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>