The cursor gets reset for QGraphicsItem when releasing the mouse

When setting a custom cursor for a QGraphicsItem and then clicking or dragging the item, then when releasing the mouse, the cursor turns into an arrow again.

The attached example demonstrates this issue.

When uncommenting the PushButton/ProxyWidget code in the example and following these steps:

1) Choosing a custom cursor and hovering over the proxy
2) Choosing another cursor, clicking or dragging the item and then releasing the mouse

-> the cursor turns into the custom cursor it had when hovering over the proxy widget. So when releasing the mouse, the QGraphicsView's cursor reverts to the previous cursor it had.