A QGraphicsProxyWidget embeds a focusable widget (e.g., QComboBox). When
deleting QGraphicsProxyWidget, the QWidget will be deleted. The QWidget
clears focus, and QWidget::hasFocus() is nice enough to check if its
embedder QGraphicsProxyWidget has focus - because if it does, it wants
to clear focus from that item too. QGraphicsItem's destructor already
calls clearFocus() however, so this call is unnecessary; we can simply
stop clearing the QWidget's focus in its destructor if the widget is
embedded.
QWidget::hasFocus checks QGraphicsItem::hasFocus (on the proxy widget
that is being deleted), which checks its d_ptr, which is gone. It's
generally unfavorable for an object deleting a child to have the child
go back and poke at the parent object, which is in many ways what's
happening here.
Task-number: QTBUG-29684
Change-Id: I1e52bf28f47b2824752de28dff2d0de13733ee48
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
843de37bca