Feature proposal: TUI drop-down menus

Micro, in my opinion, is probably the best TUI editor for beginners. It, however, lacks one very useful feature that was present in mc, mcedit and some other apps and does help beginners a lot: drop-down menus.

mcedit example:

In edit editor:

Inspired by these designs I propose to implement similar functional. Drop-down (or up?) menus can be incorporated right to existing information entries.

Some design concepts:

Shortcuts were taken from here: https://gist.github.com/rochacbruno/9e4f4c471e849276f11562272db446b0

Half-width blocks can be used to make borders wider

Or add shadows:

Color inversion can be used to highlight the currently selected tab

Box-drawing characters can be used instead of vertical bars for better looks. I also added spaces before beginning and end of lines (I wonder why they weren’t there to begin with)

One more variant with grey highlighting color:

The issue names no files, tests, or entry points. Start by clarifying the menu scope and interaction design from the examples; done would require agreed behavior and an implementation for TUI drop-down menus.