Re: Contiguous redisplay of the menu and beeps

[martin rudalics]

>>With `debug-on-error' t you do get an error from `forward-list'?
>
>
> Yes, but I don't see the "not accepting any operations" or "continuous
> redisplay" behaviors.  Maybe that part of the bug is specific to
> Windows.

I think there are three bugs:

(1) The list scanning bug in `sgml-point-entered'.  It shouldn't be a
problem to fix that, maybe it's even a non-issue once (2) gets done.

(2) A bug in redisplay.  Somewhere Qinhibit_point_motion_hooks doesn't
get bound to Qt but so far I was not able to find out where.  There's
evidence that the bug shows up when `column-number-mode' is enabled,
`current-column' is called and triggers sgml's point-entered hook.
Maybe it's got something to do with sgml's invisibility properties.
Kim would find this in five minutes, but where are thou ...

(3) A bug that may render Emacs disfunctional on Windows and is related
to menus.  I suspect this is a consequence of (2) which causes Emacs to
consume ~100% CPU and maybe interacts badly with something w32 specific
like menu_free_timer (a very wild guess, I know).

I conjecture that (2) and (3) are also responsible for the behavior
reported by Tak Ota for his table cell menu entry.