Bug 492672

Summary:	switching virtual desktop does not unmap windows
Product:	[Plasma] kwin	Reporter:	Oswald Buddenhagen <ossi>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED INTENTIONAL
Severity:	minor	CC:	kde, nate
Priority:	NOR
Version First Reported In:	5.27.11
Target Milestone:	---
Platform:	Debian unstable
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Oswald Buddenhagen 2024-09-05 08:00:49 UTC

on X11, if, and only if compositing is enabled, switching to a different virtual desktop does not unmap the windows from the previous desktop.

i suppose this is simply a result of it being (supposedly) unnecessary, as the compositor takes care of hiding the out of view windows. it also has the nice side effect that switching is rather instant.

however, it has the rather unfortunate side effect that applications don't know that they can stop repainting their windows entirely, so it causes a rather significant resource consumption problem. my go-to example for this is viewing https://www.wetteronline.de/wetter/berlin in chrome, which eats lots of cpu and gpu.

this is sort of the same as closed bug #431242.

Comment 1 David Edmundson 2025-10-08 15:25:44 UTC

Terms on wayland are different, windows do get notified via both limited frame callbacks and an occluded state.

What apps do with that is on the apps

Comment 2 Oswald Buddenhagen 2025-10-08 16:05:49 UTC

why would i care about wayland? it sucks, in some points by design, and i'm going to resist switching to it as long as feasible.

and on x11, this is a regression introduced by a specific compositor implementation. i expect somewhat more convincing arguments for keeping it that way.