For pretty much all the apps I use I have a kwin rule that sets starting virtual desktop and starting window position.
I set these using the Special Window Settings dialog via the window title bar menu.
This then opens Window Specific Settings dialog window with things like window class and window type prefilled. Clicking okay then creates a kwin rule, which I can modify if need be from System Settings -> Window Managment -> Window Rules.
This is not working for 5.14.1, no window rule is being created for any app I try and create one with. I haven't created one for a while, the apps I use is pretty static, so not sure when this was introduced.
Only error being generated is this one, every time I open any System Settings window.
Oct 20 manjaro kwin_rules_dialog[11696]: "ForegroundLink" - conversion from "73,202,1610" to QColor failed (bounds error: blue component > 255)
I've changed the color scheme to 4 or 5 very different color palettes, but it makes no difference. Not sure if this is an unrelated error or not, but it is the only info I get.
Can anyone else create Window Rules from this dialog, or is this issue peticular to my setup ... which is pretty vanilla by KDE standards.