Bug 498641 - When extremely small mouse movements are made while clicking to try to stop "flick" scrolling, the scrolling accelerates instead
Summary: When extremely small mouse movements are made while clicking to try to stop "...
Status: CONFIRMED
Alias: None
Product: okular
Classification: Applications
Component: general (show other bugs)
Version: 24.12.1
Platform: Arch Linux Linux
: NOR minor
Target Milestone: ---
Assignee: Okular developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-01-14 04:52 UTC by Kristian Buchman
Modified: 2025-01-19 01:06 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
Screenshot with QT_LOGGING_RULES="qt.widgets.scroller.debug=true;qt.pointer.velocity.debug=true" that shows the output when scrolling speeds up (3.07 MB, image/png)
2025-01-14 04:52 UTC, Kristian Buchman
Details
Screenshot with QT_LOGGING_RULES="qt.widgets.scroller.debug=true;qt.pointer.velocity.debug=true" that shows the output when scrolling stops as expected (2.49 MB, image/png)
2025-01-14 04:53 UTC, Kristian Buchman
Details

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Description Kristian Buchman 2025-01-14 04:52:02 UTC
Created attachment 177341 [details]
Screenshot with QT_LOGGING_RULES="qt.widgets.scroller.debug=true;qt.pointer.velocity.debug=true" that shows the output when scrolling speeds up

SUMMARY
I have a habit of grabbing documents, flicking up to start a scroll, and then clicking quickly to stop scrolling again. Trying to do this on Okular can produce unexpected results. 

STEPS TO REPRODUCE
1. Open in continuous mode
2. Hold and drag to start scrolling the document
3. Click very quickly

OBSERVED RESULT
Document sometimes starts scrolling very rapidly

EXPECTED RESULT
Document should stop scrolling immediately. 

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 6.2.5
KDE Frameworks Version: 6.10.0
Qt Version: 6.8.1
Kernel Version: 6.12.9-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 5600X 6-Core Processor
Memory: 15.5 GiB of RAM
Graphics Processor: AMD Radeon RX 6700 XT

ADDITIONAL INFORMATION
Comment 1 Kristian Buchman 2025-01-14 04:53:06 UTC
Created attachment 177342 [details]
Screenshot with QT_LOGGING_RULES="qt.widgets.scroller.debug=true;qt.pointer.velocity.debug=true" that shows the output when scrolling stops as expected
Comment 2 John Kizer 2025-01-18 19:16:57 UTC
Hi! Would it be possible for you to please provide a screen recording of this issue, so that folks could see the surrounding circumstances when this bug shows up?

Thanks!
Comment 3 Kristian Buchman 2025-01-18 20:20:32 UTC
Hey John,

For sure! It must be that there is a small amount of mouse movement during the click, but it feels very wrong to me. I can't replicate if I pick my mouse up.

Anyway, Here's a link 
https://www.dropbox.com/scl/fi/r21lxvz4tavrl5tj3cjc6/2025-01-13-21-31-30.mkv?rlkey=lq3dxwbh8s2wvqbg2d7vlz1zj&st=5bntrcpu&dl=0

That's a 118mb 1440p video so that the debug log is visible on each frame. 

Thanks,
Kristian
Comment 4 John Kizer 2025-01-19 01:06:19 UTC
(In reply to littlegreendude55 from comment #3)
> For sure! It must be that there is a small amount of mouse movement during
> the click, but it feels very wrong to me. I can't replicate if I pick my
> mouse up.

Thanks! I see how it's working on your system - and I can reproduce that an extremely small amount of mouse movement made while clicking causes acceleration, and that it does consistently stop if the mouse is picked up (so there's definitely no cursor movement).

I retitled to the behavior that it seems we can both confirm, if that makes sense to you as well. This would be a usability benefit to look into, I believe, especially for folks who may have trouble clicking their pointing device without any motion. Thanks!