@Bavaria Blu Re: best Windows ever
perhaps there is a keyboard shortcut to switch between extend and only on 1 screen?
There is. Windows+P cycles between "main display only", "extend desktop", "mirror displays" and "external displays only"
And, while I'm here: you can use Shift+Windows+CursorLeft and Shift+Windows+CursorRight to move the currently-focussed window between screens, and Windows+CursorUp to maximise the current window to full screen size.