Rotobrush is only usable and editable in the Layer Panel. Double click the layer you want to Rotobrush and select the tool. You should be good to go.
There are great Rotobrush tutorials in the help files. Type Rotobrush in the Search After Effects Help field at the top right corner of the app to find this: Roto Brush and Refine Matte | CS6
Thanks, but I did double click and have the layer open with the roto brush tool selected, but I still don't see everything I selected while working on it all last week.
So I guess my choices are to either go back to the end product I wasn't satisfied with before I stepped back in history, or start all over again from scratch.
I just stumbled onto the solution. Apparently I needed to click the Toggle Alpha Boundary button.
It happened again, and this time, clicking the Toggle Alpha Boundary button isn't helping.
I remained stepped back before I created the duplicate layer and I adjusted my roto brush selections in the entire clip.
The tutorial I'm following said to duplicate the layer, which I did, then delete the roto brush instance from the bottom layer.
Then it said to apply the effect I want (Gaussian blur in my case) to the top layer. I set it at 65 which worked great yesterday. But today, nothing blurred.
So I tried to find my roto brush selection, but I can't get it to turn on again, even though I am on the correct layer, in the layer panel (not the composition panel), with the roto brush selected. And using the Toggle Alpha boundary button does nothing.