Bug 435600 - Noticeable Delay switching between Kickoff categories
Summary: Noticeable Delay switching between Kickoff categories
Status: RESOLVED FIXED
Alias: None
Product: plasmashell
Classification: Plasma
Component: Application Launcher (Kickoff) (show other bugs)
Version: 5.27.3
Platform: Arch Linux Linux
: NOR minor
Target Milestone: 1.0
Assignee: David Edmundson
URL:
Keywords: usability
Depends on:
Blocks:
 
Reported: 2021-04-11 00:45 UTC by Unknown
Modified: 2024-02-03 14:58 UTC (History)
6 users (show)

See Also:
Latest Commit:
Version Fixed In: 6.0


Attachments
Video of the issue. Use mpv, along with "," and "." to step through frame by frame. (210.69 KB, video/mp4)
2021-04-11 00:45 UTC, Unknown
Details
Selector stuck doesnt follow mouse cursor (46.02 KB, image/png)
2024-02-03 14:58 UTC, Axel
Details

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Description Unknown 2021-04-11 00:45:00 UTC
Created attachment 137490 [details]
Video of the issue. Use mpv, along with "," and "." to step through frame by frame.

SUMMARY
When moving the mouse between categories in kicker, it takes ~0.25s to switch between them.
This delay is very noticeable.

(delay measured by recording and then stepping frame by frame; it varies between different categories.)

STEPS TO REPRODUCE
1. Open kickoff
2. Hover over one category
3. Hover over the next one

OBSERVED RESULT
Slight delay when switching.

EXPECTED RESULT
Switching should be instantaneous (or, (but preferably not) animated)

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.21.4
KDE Frameworks Version: 5.80.0
Qt Version: 5.15.2
Kernel Version: 5.11.2-arch1-1
OS Type: 64-bit
Graphics Platform: X11
Processors: 4 × Intel® Core™ i5-6500 CPU @ 3.20GHz
Memory: 7.6 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 530

ADDITIONAL INFORMATION
Comment 1 David Edmundson 2021-04-11 06:22:55 UTC

*** This bug has been marked as a duplicate of bug 433819 ***
Comment 2 Alve 2023-04-13 08:45:02 UTC
The issue showed in the attachment still exists (at least on 5.27.3).

It seems to be related to loading all applications in that category as it is way slower when there's more applications in the category
Comment 3 Alve 2023-04-13 08:47:45 UTC
Also, it is not a duplicate of 433819, this is another issue
Comment 4 Nate Graham 2023-12-08 22:46:03 UTC
Can reproduce in Plasma 6. Seems to have gotten a bit worse recently. It's barely noticeable when I slowly move the pointer slowly, but if I move it rapidly, the lag is easily noticeable.
Comment 5 ivan.planinar 2023-12-22 16:15:11 UTC
I thought it was caused because of the triangle-filter I and others reported years ago, but it's not. It's a bit different and depends on some categories, as Alve here said. 

IMO, the User Experience of the menus should be there in the priorities for KDE, as it's the thing users notice and use on the daily basis.
Comment 6 David Edmundson 2024-01-30 10:09:19 UTC
Is there high CPU at the same time? There's a bug of kservice cache constantly updating. I'll look into that first and then we can see what other issues remain.
Comment 7 Nate Graham 2024-01-30 15:55:11 UTC
Yes, and with debug logging turned on, I can see an endless stream of "kf.service.services: query for mimeType "x-scheme-handler/appstream" returning 1 offers" while hovering over different categories.
Comment 8 Bug Janitor Service 2024-02-01 22:28:32 UTC
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-desktop/-/merge_requests/2023
Comment 9 David Edmundson 2024-02-02 09:44:00 UTC
Git commit 2d99231da58713e3b9d5ba646a91a45e06c684b9 by David Edmundson.
Committed on 02/02/2024 at 09:34.
Pushed by davidedmundson into branch 'master'.

kickoff: Workaround Qt bug that causes excessive

ApplicationsPage tried to disable or enable sections at runtime, however
the code to disable grouping did not work quite as expected, instead it
looks up every role.

This is problematic as the model actions data role is excessively heavy,
checking service availablity.

The cause in Qt is identified and a merge review is pending.

M  +2    -1    applets/kickoff/package/contents/ui/ApplicationsPage.qml

https://invent.kde.org/plasma/plasma-desktop/-/commit/2d99231da58713e3b9d5ba646a91a45e06c684b9
Comment 10 Nate Graham 2024-02-03 05:11:16 UTC
It's pretty much fixed with that.
Comment 11 Axel 2024-02-03 14:58:44 UTC
Created attachment 165498 [details]
Selector stuck doesnt follow mouse cursor

Selector stuck doesnt follow mouse cursor

2 February 2024. Ive seen this bug previously, however what I had seen was a variation of this. 

Moving the mouse cursor on the right part works flawlessly, but in the application folders sometimes the selection gets stuck on the last folder and doesnt follow the mouse cursor. Also there is still a noticeable delay though less severe than the one appearing in the first post.

Picture of the bug taken today. if mouse cursor unmoved the selector remains stuck there indefinitely