Created attachment 95759 [details] a screenshort kde 4 & 5 dual screensmode: scale "maximize" isn't correct on my primary screen if this screen has a right vertical panel and not important where is my second screen - on left or on right
The problem is that you have a panel between screens which is not supported. Famous words: "Wayland will fix it". *** This bug has been marked as a duplicate of bug 167852 ***
(In reply to Martin Gräßlin from comment #1) > Famous words: "Wayland will fix it". Ftr: despite this not being specified, we actually could add a proprietary property to plasmashell + kwin to support this in at least that constellation. Given the wayland situation (semi vendor lock-in) and self contained gnome-shell (being the second major DE), we could just as much today stop caring about the rather stalled fdo specs :-( and fix things "for us", by introducing _KDE_WM and _KDE_WM_XP (latter for "things we try, don't rely on it") Other interested clients (lxqt) can then just make use of those at will (and by the promise that "our" specs won't ever use the term "should" ;-)