Not seeing both cameras in Multi Camera View
I know there have been a zillion questions on this topic but I didn't understand the answers so here we go again...
( Premiere Pro 2015.2 release, CC version 9.2 )
I have a Multicam sequence with two video tracks and an audio track created with Create Multi Camera Source Sequence. I've toggled Multi Camera View on but one of the views remains black.
Each video track can independently be displayed in the right-hand viewer, say by disabling the other one with the little "eye" icon - toggle track output, but my understanding was that I should be able to see both cameras at the same time.
Screen shot...

I've seen people say it has something to do with "targeting" but I don't really understand what that means.
Thanks in advance for any advice!
