After recent fixes these two keys work in a strange way:
1. F1 does two things instead of one: it opens help and selects F1 in combobox (but in Windows 7 it can't select F1 when drop-down list is opened).

Please make its behaviour stable. You can either make it just selecting F1 key (there is a Help button in dialog for ones who will need help when combobox is focused), or you can make it working as Esc (first press selects F1 and second one opens help), or it may just always open help with no singularities.
2. F4 now select F4 key in combobox, but some people use F4 for opening/closing drop-down combobox menus.

Please return system behaviour to F4 key in opened drop-down list.