Hello,

I have several desktops, let's say I have Firefox open on Desktop 1 and Konsole on Desktop two, when I now click on a link in Konsole it is being opened in Firefox and the Firefox window is being moved automatically to Desktop 2.
How can I prevent this behavior so that windows are never moved to another desktop automatically?

It's a bug in Firefox. The only ways to prevent it from jumping desktops is to either force it to the desktop with KWin window rules (Alt+F3 -> Advanced -> Special Application Settings) or set the "browser.tabs.loadDivertedInBackground" setting in Firefox's "about:config" to "true". The second method will also prevent Firefox from ever stealing focus when you open a link from another application at the same time.