As soon as we receive an event not related to dragging
a QDockWidget out of its area (or a similar use case),
we no longer need the forward window.
Task-number: QTBUG-37265
Change-Id: I310e9cc2cf099c76e7a88427826d4b97ca0cd9b9
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>