bug#51490: Show an indicator when Emacs is busy somewhere in the Emacs window

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> Mode line is drawn in C, not in Lisp.
>
> And if the problem is that we cannot run the display code, either,
> then how would it help to poke the glyph?  It won't be shown on the
> glass, because redisplay cannot run.  Right?  Or what am I missing?

Redisplay can run, but we can't run any Lisp code, and the normal
formatting of a mode line does (potentially) run lots of Lisp code,
doesn't it?