Hiding menus when in conversation of Wait()ing

[bx83]

I have a top-bar menu which is invisible most of the time, but comes into view when you move the mouse cursor over the general area.
How can I get it to *not* display (or display greyed out?) when I'm a) in conversation (dialog) or b) during a process that is blocking ?

[bx83]

General Settings -> Visual -> (when player interface is disabled, GUIs should) Be Hidden.

So yeah, figured that out pretty quick :p