Trapped in Dope Sheet view I've used Blender a bit, so I've been enjoying how usability has improved in v2.8, but I was in Animation view - timeline, dope sheet and view - and accidentally touched the keyboard - POW! The view changed to only the dope sheet. No menu items along the top, no '+' or little black rounded triangles in the corners to let me drag open new windows, nothing.

So I re-started, and got the menus back along the top; I can open the alternative views, but Animation is stuck on just Dope Sheet, nothing else. I have tried every keystroke/combination/mouse-clicks, but the only points on the screen where I get up&amp;down arrow (indication I can click &amp; drag) don't do anything. Just the Dope Sheet. How do I get more windows open?
Ah! I tried ctrl-spacebar, which had no effect, but then accidentally tapped the alt key (yes, clumsy of me, I was trying to do this while holding a cup of tea), and the original view came back. 

So the answer is, 3-key combination: Ctrl - Alt - Space bar.
This toggles 'full screen' for whatever view the mouse is hovering over.

Thanks moonbots!