Philipp Stephani <p.stephani2@gmail.com> schrieb am Fr., 9. Sep. 2016 um 18:29 Uhr:Philipp Stephani <p.stephani2@gmail.com> schrieb am Fr., 9. Sep. 2016 um 18:20 Uhr:Eli Zaretskii <eliz@gnu.org> schrieb am Fr., 9. Sep. 2016 um 18:07 Uhr:> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Fri, 09 Sep 2016 15:59:02 +0000
> Cc: 24372@debbugs.gnu.org
>
> Eli Zaretskii <eliz@gnu.org> schrieb am Di., 6. Sep. 2016 um 18:03 Uhr:
>
> > From: Philipp Stephani <p.stephani2@gmail.com>
> > Date: Mon, 05 Sep 2016 21:16:40 +0200
> >
> > emacs -Q -eval '(setq blink-cursor-delay 0.0)'
> >
> > Move point around in the scratch buffer (e.g. press C-b a couple of
> > times): the cursor stays visible, as it should be. Then put the mouse
> > focus on a different GTK window (not Emacs window), put the mouse focus
> > back on Emacs, and move point again: the cursor is hidden, making it
> > impossible to see until you stop moving.
>
> Does it happen even if you wait with cursor motion until after the
> cursor blinks one time, i.e. if you start moving point with the cursor
> already visible after Emacs gets focus?
>
> Yes. No matter what state the cursor is in and how often it has already blinked, it becomes invisible when
> moving.
So what is the importance of moving focus out of the Emacs frame and
then back into it? Is the problem reproducible without that? Or are
you saying that focus-out followed by focus-in event somehow changes
the behavior wrt displaying the cursor?Yes. The cursor only become invisible after a focus-out/focus-in event.This isn't surprising given that blink-cursor-mode changes focus-in-hook and focus-out-hook. Probably the bug is hidden somewhere in the complex interaction between the various blink-cursor timers and hooks.A simpler recipe that doesn't need explicit focus events isemacs -Q -eval '(progn (setq blink-cursor-delay 0.0) (blink-cursor-suspend) (blink-cursor-check))'and then start moving point.OK, I guess one issue is that setting blink-cursor-delay doesn't restart blink-cursor-idle-timer. (Similarly, changing blink-cursor-interval doesn't restart blink-cursor-timer.) While obviously we can't fix that when using setq, I'd suggest adding custom setters to the variables nevertheless.The direct cause of the issue seems to be that, when blink-cursor-delay is idle, after every command blink-cursor-start is called immediately, which hides the cursor. I guess that is so that in the default case where blink-cursor-delay = blink-cursor-interval the cursor frequency is constant. However, this causes the cursor to be hidden very quickly when blink-cursor-delay < blink-cursor-interval. Maybe in that case blink-cursor-start should show instead of hide the cursor, and run-with-timer should be called with an argument of (blink-cursor-interval - blink-cursor-delay), so that the cursor is at least shown for blink-cursor-interval. WDYT?