1

A number of menu items shown under Edit are greyed out when the RT editor is used - caveat, they still work when initiated with a keyboard shortcut (examples cmd-z and cmd-y). When switching to the Markdown editor these commands can again be selected from the menu (not greyed out any more).
(this happens on the mac desktop version)

2

Just realize that this b(ug)ehaviour is still in place in version 1.8.2., at least under osx.

3

Yes I think the commands would somehow need to be tweaked so that they work with the Rich Text editor too.