Usability: Programatically allow ComboBox to popup upwards

Currently, QComboBox's popup appears below the combo box, unless there is not enough space to the bottom of the screen.

Now, if a combo box is in the status bar of a maximized window, it will pop down when there are only few items, otherwise the popup will appear above the combo box.

To ensure a better user experience, it would be nice if the designer/developer could tell the combo box to prefer popping upwards, even though there might be just enough space to the bottom of the screen. This would make sure that every opening of the combo box will be in the same direction, no matter how many items are in the list. Also makes sure that "click + cursor up" movement will work consistently for the combo box, independent of the number of items in the list.