Vertical Bar at the edge of Final Frame

Hey Folks,

I find that most of the problems I come across, for me anyways, are that I don't know what to call "the thing" I'm looking for.

Here's a perfect example of what I mean which I'm calling the "Vertical Bar at the Edge of the Final Frame of my Video/Movie"  What...?  No worries, I've a ttached a screen shot.

Can someone name that Bar?

Peace,

ElementX