Extended selection only selects 2 items when shift is hold

I noticed since Qt 4.6 beta when we create a QListView or QListWidget and there are more items than displayed ones (if widget has 20 items and only 10 are displayed), if we are using ExtendedSelection and we try to select the last items while holding shift key, only 2 items are selected.

I attached a minimal example (I can't do smaller), by default, the window should display 10 items on the 20 created.

To reproduce the bug :

1. go to the end of the QListWidget
2. click on the last item with left mouse button
3. press shift key and keep holding it
4. press the top arrow to select the previous item (shift key must be hold)
5. repeat step 4 until only 2 items are selected

If you resize the window to display all items, the bug is not occuring anymore.