1) hit "a" to insert a new tab into the tabwidget
2) switch to the second tab
3) try to click on the QTextEdit to give it focus
4) the QTextEdit never gets focus, however still recieves keyboard input.

The scene's isActive function returns false and thus never passes the focusInEvent on to the QGraphicsItem.

I believe this is the reason. When the QGraphicsView is inserted into the QTabWidget. The widget is hidden, thus setting activationRefCount in the QGraphicsScene to -1 and the subsequent show call would set activationRefCount to zero. This would then never allow the QGraphicsScene to be active.

I am actually using the head 4.7 branch. Also tested on qt 4.6.2. I attached a sample application.