Quote Originally Posted by hickscorp View Post
An Optimization? i'm not sure i understand...
There is no point in tracking mouse position on the items (which requires coordinate transformations and collision detection) if you know the mouse is not in any of the views that hold the items. There is no point in tracking the mouse to detect hover events if you know the mouse is not over the item, etc. I'd assume it's exactly the same for widgets, although it might be a bit different as there is no scene equivalent for widgets so you'd post the event directly to the widget and this will probably just work (although Qt will not try to detect hover events by itself).

Now i've pointed it out, you know it's an optimization?
It's just logical to assume so. Qt is open source, you can easily verify my assumption by reading its source code.

Why not telling it in the doc then?...
If every detail was covered in the docs and every possible abuse of Qt was warned about in the docs, then the docs would have several gigabytes of volume and there would still be creative people who would invent new ways of abusing Qt.