While working in paper-space, you may be wanting to simply move things around. The trouble sometimes is accidentally activating an unlocked viewport and messing up the correct position or scale of the that viewport. In a perfect world, the viewport should be locked to prevent such accidents. However, if you want to just do the edits without worrying about activating the viewport, here is a secret variable that is undocumented and isn’t shown in the variable editor.
NOTE: If you do change this system variable while editing, don’t forget to change this system variable back to normal in case someone else needs to activate a viewport.
- SPACESWITCH <enter>
- <0> = OFF – makes it so that you cannot double click within a viewport to activate the viewport.
- <1> = ON – (default) allows you to double click to activate a viewport.
AutoCAD Tips 
Will this command work if the View-port is already activated (current)?
I have experienced inability to exit active View-ports due to close-up zooms.
If you are stuck in a viewport and want to get back into paper space use PS . or PSPACE . This will set you back into paper space so that you can scroll back out.
Also – while you are in paper space, you can use MS or MSPACE to jump into a viewport but this isn’t as quick as double clicking.
~Greg