As a result of using QWidget::setVisible to show the child widgets we
would end up also setting ExplicitShowHide. This is not in line with
the intent of ExplicitShowHide, which is to flag a widget as explicitly
shown/hidden by the developer, which in turn prevents Qt Widgets from
toggling WState_Hidden when the widget is reparented.
By using QWidgetPrivate::setVisible instead, we can show the child
without setting ExplicitShowHide.
As side effect of this is that we no longer reset WA_WState_Hidden
from QWidgetWindowPrivate::setVisible(). This is an issue when the
setVisible call comes as a result of destroying the QWidgetWindow,
as that is an implicit hide, and should not result in the widget
having WA_WState_Hidden. QWidget handles this case in hideChildren
by not calling QWidgetPrivate::setVisible -- instead doing its own
reset of WA_WState_Visible. We don't want to untangle this just yet,
so as a workaround we detect that the widget is already !isVisible(),
thanks to hideChildren having hidden it, and then skip the call
to QWidgetPrivate::setVisible that results from QWindow::destroy().
Task-number: QTBUG-121398
Pick-to: 6.7
Change-Id: Ib5b4d9c84f0569124c5f3ca2169cabff18934e2d
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>
5ba0982b28