When in Text View, if you scroll through the text (so that it’s not in the default home position at the top), then try to select a portion of text, the page will ‘jump’ a few lines. If you click to insert the cursor before doing this, everything is fine, but if you go straight to select the text whilst the focus is somewhere else, then it jumps (which makes you select the wrong thing). Only minor, but I thought you would like to know! 
I don’t know if you have the typewriter option turned on for your editor, but that will cause the kind of jumping you are talking about. It just wants to make the place you click be the center of the screen.
Yes! Many thanks - now I feel suitably foolish. 
I’m new to Scrivener - I was wondering what that option meant! 