Once connected to external display, all my open windows move, why?

Am running KDE on my laptop and every time that i connect an external display, all my open windows move over to the external display and i have to manually bring them back to the default laptop display.

Any suggestions/ solution for this?

I don’t know anything KDE specific but I guess you have a similar functionality - which can set the primary display.

It exist with Nvidia and XFCE and most likely you will have something similiar.

I have already set my laptop screen as the default and external as secondary but still the same same thing happens.