Support Menu key in addition to right click (on Microsoft Windows keyboards)

[CyberTailor]

This key is present on some keyboard. It's used to open context menus. https://en.wikipedia.org/wiki/Menu_key

[skyjake]

I suppose the underlying use case here is to enable using context menus without lifting one's hand to the mouse? As in, press the Menu key, then select and activate a menu item via cursor/shortcut/Enter keys.

Fully implementing this will require enhancing the keyboard-based UI navigation, also enabling #144.