I'm sorry to give you such a short answer to your detailed suggestion but, unfortunately, because QAP is relying on the Windows standard menus engine, it has no control on the behaviour of the menu itself. QAP can create menu, set some properties but, once the menu is displayed, it can control the menu reaction to user input. QAP takes the control back only when a user select an item in the menu.
I agree with you that there is room for improvement in Windows menus (especially with you have multiple columns). We could make these suggestions to Microsoft but with their current focus on interoperability and new platforms, I doubt they will work on these "legacy" menus.
The alternative would be to completely rewrite the QAP menu (using the AHK platform and much advanced libraries) but this would be way too much work and would open the door to a whole new set of bugs and issues. Sorry but this is not on the QAP roadmap.
See
other examples of things that can't be done by QAP.