High Sierra Screenshot part of screen stopped working I have been for years using shift+cmd+4 to take a screenshot of only a part of the screen, or just to measure some distance in an image. A week or so ago it completely changed functionality to instead take a screenshot of the entire hovered window... Why?? I need it back.. I get designs as JPG's :D and need to implement websites base on that :P

I haven't installed anything that I can think of, I got a new external screen but that was plug &amp; play, a DELL screen. It can't be that can it?? 

Attaching a photo of how it looks below, note the blue tint that the window is selected and the camera icon in the middle..
I'm not sure what has prompted it to default to 'whole window' - usually 'selected area' is the default, however, tapping the Space Bar should toggle the behaviour back &amp; forth for that session.