Tooltips possible with QGraphicsProxyWidget?

Is it possible to use tooltips on widgets that is place in a QScene with QGraphicsProxyWidget?

The following is a simplified version of what I am trying to do:

Code:

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QListWidget* list = new QListWidget();
list->setToolTip("This is my tooltip");
QGraphicsScene* scene = new QGraphicsScene();
scene->addWidget(list);

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I can see my listbox and I can click and select items, etc. But the tooltip is never displayed.

With version 4.6.2 this feature was broken.

Version 4.6.3 fixed this for the QListWidget, but the QPushButton's tooltip only works if you move the mouse from one button to another. If you move the mouse over a button with a tooltip, off the button and back to the SAME button, the tooltip text is empty. :(