Hi,
I work with two screens. When I maximize windows on the primary screen they are overlaped (usually the status line of the windows becomes invisible) by KDE's windows bar. To adjust the size of all windows by hand whenever I connect the second screen is a lot of work. I would like to maximize the windows in a way which is aware of the window bar or to adjust the size of all windows automatically.
Thanks!

By "KDE's windows bar", are you referring to the panel (which shows the application launcher, tasks, clock, system tray etc.)?

Yes, the window bar (list) is taking most of the space in my panel.

where is your panel located? Between the screens?

The panel is at the bottom of the main screen (VGA1). It is completely visible and works flawlessly but maximized windows don't seem to know about its presence. Thats different when I work on a single screen.

you likely found https://bugs.kde.org/show_bug.cgi?id=167852
if your second screen is not configured to be below the primary one, you found sth. else

Another thing to check is the panel visibility, it must be "Always Visible" otherwise windows can be covered by it.

Thanks luebking, I think this is the solution I am now always working with the main screen below.