Subject: bug#28652: 26.0.60; Display often "flashes" due to double buffering when switching to Emacs frames

From: Lars Ingebrigtsen <[email-masked]>
Date: Fri, 03 Sep 2021 09:57:17 +0200

[email-masked] (N. Jackson) writes:

> When switching between windows in Gnome using Alt-Tab there is
> often a bright flash just after switching to an Emacs frame.
>
> It seems as if the Emacs frame is displayed and then a window of
> some other application appears for a fraction of a second before
> the display settles down to the showing the Emacs frame.
>
> Because the flash is so quick, I Initially thought the Emacs frame
> was being displayed in white before being painted to it's correct
> display, but this is not the case. By choosing distinctive colours
> or distinctive images in my other applications, I can tell that it
> is the window of another application that is flashing up.
>
> [This flashing might be particularly noticeable on this system as
> I use a dark theme in Emacs (Wheatgrass) and most other
> application windows are predominantly white. Also I keep all my
> Emacs frames and all my other application windows maximised or
> full screen (because I have a small display).]

(I'm going through old bug reports that unfortunately weren't resolved
at the time.)

I'm also using Gnome (I'm on Debian bullseye), but I can't see these
flashes (I've tried in Emacs 26.1 and Emacs 28) when Alt-Tab-ing between
something that has a bright background and Emacs (which has a black
background).

Are you still seeing this in recent Emacs/Gnome versions?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no