Bug 368374

Summary:	panel application previews appear to freeze screen for long periods
Product:	[Plasma] plasmashell	Reporter:	davidblunkett <dav1dblunk3tt>
Component:	Task Manager and Icons-Only Task Manager widgets	Assignee:	Eike Hein <hein>
Status:	RESOLVED FIXED
Severity:	normal	CC:	jmjudeb, nate, notuxius, plasma-bugs, subdiff
Priority:	NOR
Version:	5.5.5
Target Milestone:	1.0
Platform:	Kubuntu
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description davidblunkett 2016-09-07 07:28:26 UTC

I was working on ~50 pdf documents in okular - this put 50 instances of okular in the task manager and they stacked into one button.  To navigate I wanted to right click, get a menu, and select the correct document.

If I wasn't quick enough to right click then the preview that is provoked by hovering would kick in and this could freeze the screen for several seconds.

Reproducible: Always

Steps to Reproduce:
Start many instance of an application so they stack in the task manager

hover over the task manager button

screen <sometimes> freezes generating previews

Actual Results:  
Screen freezes

Expected Results:  
Shouldn't freeze

Comment 1 jmjudeb 2017-01-19 19:59:09 UTC

I am also affected by this bug, when starting ~30 xterms.  I can work around the problem by turning off grouping.

Using: plasma-desktop 4:5.8.5-0ubuntu1~ubuntu16.04~ppa1

Comment 2 Eike Hein 2017-01-19 20:04:14 UTC

Also seeing this lately.

Comment 3 Roman Gilg 2017-01-23 17:11:17 UTC

Since it's in 5.8, it is probably not related to the tooltip redesign in 5.9. I speculate, that it's because of all thumbnails being rendered at the same time. To confirm this, try to minimize most of the 50 windows. Then thumbnail loading should be aborted (as long as not activated in system settings) and there should be no freeze.

Comment 4 Alexander Mentyu 2018-02-28 07:27:27 UTC

Preview loads a little longer than usual - CPU usage increases upon hovering but screen isn't freezing for long periods - tried with ~150 instances of Okular with opened files

Plasma: 5.12.2
Apps: 17.12.2
Frameworks: 5.43.0
Qt: 5.10.1
Kernel: 4.14.20-2-MANJARO
OS: Netrunner Rolling

Comment 5 Nate Graham 2018-02-28 16:42:10 UTC

Same; let's call this fixed. David, please re-open if you can still see this with KDE Plasma 5.12.2 or later.

Comment 6 davidblunkett 2018-02-28 21:22:48 UTC

Ok - I'm happy with that - thanks!