Yes...this is like most programs where everything is in layers.
I only have two videos. One main and another that is in PiP 1. (They are both the same movie but from different camera angles. I recorded an event with two cameras simultaneously.)
Like you said, video and audtio may be layered, but with only two layers (main and PiP 1) and no other PiP strings activated, I can't figure out how to make this one clip visible.
Even when I highlight the clip and click on the MODIFY button, I still do not see the clip...it shows the main clip.
There has to be a way to move the PiP to the front.
(What makes this bad is that this 3 second PiP clip is what is holding me up from rendering the entire show. The rest of my project is done. Ain't that the luck!)