Steps to reproduce shows the problem clearly: 1. Open Canvas Input Settings (settings -> configure krita... -> canvas input settings). 2. Open one of the sections, e.g. Pan Canvas. 3. Click on "Add shortcut..." at the bottom of the table 4. Set the Type to Mouse Wheel. 5. Double click on the Input cell ("None" by default) to show the input/modifier settings. From here, I would click on "Mouse Wheel" and then scroll my wheel in a direction, e.g. up. This would set the value to Mouse Wheel Up (etc). However, on my Linux system, *the scroll wheel is not detected.* Thus, I can't set the setting. I should note that the scroll wheel *does* work correctly within the actual paint UI - I can zoom in/out with the scroll wheel just fine (there's a setting "Zoom Canvas" -> "Mouse Wheel Down: Zoom Out"). It's just that the settings UI doesn't detect my mouse wheel. I propose that, rather than that setting require the user to scroll their mouse wheel (which, of course, needs it to be detectable through the UI - which evidently isn't always the case), there should be a dropdown menu with the possible options in it ("Mouse Wheel Down", "Mouse Wheel Up"). Another case of this being a particularly bad problem would be if I accidentally removed the binding for zooming in/out - then I'd never be able to use the mouse to zoom, because the setting would be gone and I'd not be able to restore it! (I could restore all defaults, but then any other settings I'd made would be gone.) (This obviously should also be extended to the other options, like "Mouse Button", but just implementing it for "Mouse Wheel" would fix this particular case.) [This is my first bug/feature report here, so, sorry if I've forgotten to provide any other useful information. For what it's relevant, I'm running Krita on Debian testing, using Gnome Xorg (not wayland).)
Created attachment 109522 [details] Screenshot posted by rad_ captured - note "Mouse Wheel Up", which rad_ set by scrolling after clicking the "Mouse Wheel (None)" button I mentioned.
Quick clarification on this: > From here, I would click on "Mouse Wheel" and then scroll my wheel in a direction, e.g. up. This would set the value to Mouse Wheel Up (etc). However, on my Linux system, *the scroll wheel is not detected.* Thus, I can't set the setting. [..] It's just that the settings UI doesn't detect my mouse wheel. On Windows, it does detect the mouse wheel. See the attached screenshot (which rad_ from freenode #krita captured).
This has been fixed when Qt moved to a new xcb implementation; turns out it was never a bug in Krita itself.