Thank you for all of the tips and pointers, but I feel like I am missing something fundamental. (Perhaps the fundamental thing I am missing is some basic training on the tool!).
Please forgive my ignorance, but I am confused by phrases such as "all you do is just activate the viewport", "You have to be physically inside the viewport though, not just in the layout the viewport is located on", and "Double-click inside each VIEWPORT".
So perhaps I should start by describing what I am trying to do...
I have imported a picture and am trying to trace the outlines that I see on the picture. There is some fuzzyness to the outlines, so I would like to trace (and then dimension) the outsides of the fuzzy objects on one layer, and then trace (and dimension) the insides of the fuzzy objects on another layer. I have (perhaps) attached a screenshot showing what I mean.
I would like to create a print showing the locations and dimensions of the outside traces, and a separate print showing the location and dimensions of the inside traces.
It is possible that I am confusing "Layouts" and "Viewports". I was thinking that each p-space layout indicated a different print, and that I could (somehow) specify which layers would be included on that print/layout/viewport.
As I said, I appreciate all of the tips you folks have given me regarding this, but I am still confused (if that's not obvious by now).
I can click on one of the layout tabs... is that what you mean by "Activate a viewport"?
I can open the layout manager and specify which layers are visible (by clicking on the light bulb icon). But when I switch to a different layout tab and change those, they are changed for all of the layout tabs.
I am not sure how to be "physically inside a viewport", and I cannot double click inside the viewport (or, perhaps I am misunderstanding what a "viewport" is). As soon as I click the mouse button once, the cursor displays a message saying "Specify opposite corner or ...".
Once again, any tips or suggestions are welcome.
--wpd