Investigating QCocoaWindow::setVisible idempotence revealed that our
QCocoaEventDispatcherPrivate::beginModalSession() implementation would
happily add the same window multiple times, resulting in trying to
re-start a modal session for the same window when the window was
closed, confusing AppKit's logic for choosing the next key window
when a modal window is closed.
We now bail out if we detect this scenario, even if setVisible has
been fixed. Additional logging has also been added.
Pick-to: 6.6 6.5
Change-Id: I07418c12b421fb0b4ebf875050e32f56fdad6197
Reviewed-by: Doris Verria <doris.verria@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
78cb91c5ca