Created attachment 129281 [details] OSD with offset background Running everything on git master with openSUSE Tumbleweed. With a 4k screen, I'm seeing that plasma dialogs are offsetting the background rect from the frame, leading to transparency in the top and left edges. This reproduces for me on both X11 and Wayland. It reproduces with any scale factor, from 100% to 250%. It reproduces when setting PLASMA_USE_QT_SCALING, and when not. In other words it is always reproducible for me. Two things changed to make me start experiencing this issue: I got a new machine with a 4K screen, and my distro shipped Qt 5.15. I am unsure if the issue is caused by one, or both, or something else entirely. Either way it's very strange.
Created attachment 129282 [details] Notification with offset background
Created attachment 129283 [details] Task Manager tooltip with offset background
This seems to have gotten fixed recently.