It is good practice to not make the expanded combobox larger than the dialog itself.
CBS_NOINTEGRALHEIGHT will allow to set a fixed amount of pixels for the v6 combobox,
and therefore allows us to hide the problem for this specific dialog.
The problem was unhidden by 0.4.12-dev-882-g e3e173ffaa
Even after this patch I think Wines comctl32 can be improved for comboboxes with very
many elements that do not use this small trick yet. I will create a follow-up-ticket.