Normally you can just escape a viewport in paperspace by double clicking on the paperspace margin, but what if you were zoomed in too closely when you entered the simulated model space from paper space?
There is a button that exists just for such occasions and it is located with your snapping tools on the bottom toolbar. Unfortunately, a bug often prevents this button from appearing. So, in AutoCAD you need to click the tray settings dropdown in the bottom right hand corner and enable the "Model/Paper Space" button.
Arg, my paper space looks like model space!
