SUMMARY When viewing the More Information screen in an offline System upgrade list of packages, if you scroll up (especially with pixel scrolling like with a touchpad), paragraphs won't be rendered until they are completely in view. STEPS TO REPRODUCE 1. Wait until there are a number of offline system updates ready to install 2. Open Discover 3. Click Updates 4. Click System upgrade 5. Click More Information 6. Scroll down a bit 7. Scroll up slowly (e.g. with a touchpad pixel scrolling) OBSERVED RESULT Paragraphs scrolling into view at the top of the window won't appear until the top of the paragraph is in view, leaving gaps until that point. EXPECTED RESULT Bottoms of paragraphs appear as soon as they are in view immediately. SOFTWARE/OS VERSIONS Operating System: openSUSE Tumbleweed 20250410 KDE Plasma Version: 6.3.4 KDE Frameworks Version: 6.12.0 Qt Version: 6.9.0 Kernel Version: 6.14.1-1-default (64-bit) Graphics Platform: X11
Created attachment 180285 [details] A video demonstration of the issue Note that I have deliberately made the window narrow to emphasise the problem, but it is visible in wide windows too.
I can reproduce this with Neon Testing, which also has the "System upgrade" offline update category KDE Plasma 6.3.80 KF: 6.14.0 Qt version: 6.8.2 Wayland
I cannot reproduce this on Fedora 41 Wayland, with Discover built from git master. Scrolling up slowly pixel-by-pixel displays the content as I would expect, not as shown in the video.
John, can you reproduce this with Plasma 6.4 or later, in the Wayland session?
I can no longer reproduce this in 6.4.5, in Wayland or in X11, so it looks like it's been fixed in the meantime :)
Hmm, might have spoken too soon, as it's now happening with a different batch of updates. It might depend on how long the list of updates is, i.e. how many paragraphs there are. Yesterday it seemed OK with about 20 updates, today it's playing up with a list of about 90 updates. This will be very distro-specific, of course, as different distros use different package descriptions.
Created attachment 185221 [details] Another demo of the problem, in 6.4.5 Wayland session, just to show it's still happening
Well darn. I'm not currently able to reproduce this in Plasma 6.4.5 or git-master with about a dozen updates under System upgrade. Unfortunately I wasn't able to test this in Neon again, since opening the Updates tab made Discover crash. I'll keep this open so others can try to reproduce.
So this definitely seems to be related to how many updates (or probably more accurately, how many paragraphs of text) there are to scroll through. I received an upgrade from openSUSE with a couple of hundred updated packages. I painstakingly manually installed about five at a time, checking this bug after each batch, and the issue was present with around 40 updates, but not present with fewer than around that.
Created attachment 185468 [details] A demo of the problem, showing transition of when it happens and when it does not I've managed to capture the transition from when the bug occurs (in this instance, with 30 updates), then after manually installing one update, the bug doesn't occur with 29 updates. The threshold will vary depending on the length of release notes of the updates.