Cover Grid background texture flickers when scrolling

[aviss667]

I've noticed a change in how the Cover Grid background texture behaves between calibre versions and I'm not sure if it's intentional...

In calibre 9.9, when scrolling through the Cover Grid with a background texture set, the texture shifts/tile horizontally with each scroll movement instead of staying in place. Switching focus away from the calibre window and back temporarily restores it, but it breaks again on the next scroll.

I tried downgrading and in calibre 7.6.0 the texture stays completely still while scrolling, which feels like the correct behavior.

I tested on Windows 10, Windows 11 and Kubuntu- same behavior on all three with calibre 9.9

I filed a bug report but it was marked as invalid since Kovid explained that the background is meant to be a tiling texture. However I believe the issue isn't the tiling itself but the fact that the texture moves/redraws incorrectly during scrolling, which didn't happen in older version.

I have a video showing the problem:
https://www.youtube.com/watch?v=enYyKMajznQ

Not sure if I can create another bug report so I'm asking here. Has anyone else noticed this? Can anyone reproduce it on their end?

Thanks