Bug 476483

Summary:	Scrollbar handles are incorrectly sized and positioned until the window is resized
Product:	[Frameworks and Libraries] frameworks-qqc2-desktop-style	Reporter:	Nate Graham <nate>
Component:	general	Assignee:	kdelibs bugs <kdelibs-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	ahiemstra, kde, me, noahadvs, notmart
Priority:	NOR	Keywords:	qt6, regression
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Other
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=473241
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Nate Graham 2023-11-02 21:17:24 UTC

Plasma 6 Wayland built from git master against Qt 6.5.2


STEPS TO REPRODUCE
1. Run any QML-based KDE app that has scrollviews using the default qqc2-desktop-style. Apps that exhibit it:
- System Settings
- Discover
- Cuttlefish
- NeoChat
- Scrollable views in Plasma widget config pages
2. Look at the scroll handle in a scrollable view


OBSERVED RESULT
The handle suffers from a variety of interrelated issues:
- Initial size is too small
- When dragged, the handle does not follow the cursor
- Then scrolled using a touchpad or a mouse wheel, the handle does not move at all until you've scrolled a certain distance, or scrolled all the way to the bottom at least once


EXPECTED RESULT
None of those things happen


ADDITIONAL INFORMATION
When you resize the window, the scroll handle's problems disappear and it returns to normal.

Does not happen with qqc2-breeze-style.

This only started happening 2 days ago. I tried bisecting qqc2-desktop-style, but was unsuccessful.

Comment 1 ratijas 2023-11-06 14:50:39 UTC

You are describing all the bugs of Qt 6.5 + KF5 scroll bars. Are you sure a system-wide import PATH isn't leaking into your setup? Can you even deliberately break the scrollbars by messing up with ScrollBar.qml and rebuilding & running again?

Comment 2 Nate Graham 2023-11-09 22:08:24 UTC

Oh, if it's a known Qt 6.5 issue, that explains it as I still haven't upgraded to 6.6. Is it fixed in 6.6?

Comment 3 ratijas 2023-11-11 09:24:26 UTC

I haven't had any issues since https://invent.kde.org/frameworks/qqc2-desktop-style/-/merge_requests/280 got merged

Comment 4 Nate Graham 2023-11-11 17:10:15 UTC

Just upgraded to Qt 6.6 and indeed, everything is fixed.

Comment 5 Bug Janitor Service 2023-11-15 22:14:52 UTC

A possibly relevant merge request was started @ https://invent.kde.org/frameworks/qqc2-desktop-style/-/merge_requests/320

Comment 6 ratijas 2023-11-15 23:11:00 UTC

Git commit f6f39673e58e42ab195a44ab39dfea1c6b59ee6c by ivan tkachenko.
Committed on 15/11/2023 at 23:14.
Pushed by ratijas into branch 'master'.

ScrollBar: Drop workaround for size being initially stuck on Qt 6

Fixed upstream for Qt 6.6+

M  +1    -6    org.kde.desktop/ScrollBar.qml

https://invent.kde.org/frameworks/qqc2-desktop-style/-/commit/f6f39673e58e42ab195a44ab39dfea1c6b59ee6c