Created attachment 127799 [details] A screenshot of the off-by-one snapping it kcm SUMMARY: I have 3 monitors (all Full HD, 1920x180). If I snap them together in the kcm module, all two (not the one which starts at the top left corner) land one by one pixel off (see attachment). I've noticed that this off-by-one somehow sums how, so I got it to got off by one. STEPS TO REPRODUCE 1. Have three monitor arranged similarly like mine 2. Move the top right ne away for now, so the others make L shape (the bottom one snaps correctly at x=1080) 3. Move the top right back to the others and let it snap in. It will land at x=1079, so it is off by one OBSERVED RESULT The wrong snapping is saved as the screen layout, which means one column off pixels is one the wrong screen EXPECTED RESULT It should snap at x=1080. SOFTWARE/OS VERSIONS Linux/KDE Plasma: KDE Plasma Version: 5.18.4 KDE Frameworks Version: 5.69.0 Qt Version: 5.14.2 ADDITIONAL INFORMATION It snaps correctly, if I let it snap only against one screen edge, but with both, it is off by one.
Happens to me too. What's weird is that in my display arrangement (two screens both 1080p, main on the left), the displayed values are the right ones (left: 0,0; right: 1920,0) but a column of the focused screen's wallpaper is displayed on the other screen and if an application snaps to the edge that is common to both screens a column of pixels will appear on the other screen
Thank you for the bug report. Unfortunately we were not able to get to it yet. Can we ask you to please check if this is still an issue with Plasma 5.25 or 5.26? If it is, please change the status to CONFIRMED when replying. If not, or if you can't because you no longer use this setup, you can change the status to RESOLVED WORKSFORME. Thanks a lot!
Created attachment 153712 [details] Off-by-one snapping (should be 1920 instead of 1919) Just tested it, it is still the case with Plasma 5.26.3. (See new screenshot)
Ah yes, this. It was just fixed for Plasma 5.25.4, in fact. *** This bug has been marked as a duplicate of bug 455394 ***