Can only see one object at a time on timeline

MediocrityIncarnate

My timeline has a large bar at the bottom, which I don't see in older timeline tutorials on Youtube.  I'm sure the bar has some function, but I can't figure out what it is, and right now it's blocking me from being able to see more than a single object at a time on my timeline. 

I can't shrink the bottom bar any further than this.  I can expand the total timeline area, but for the moment I'm working with one monitor, so expanding it significantly eats into the rest of my screen real estate. 

What is this bottom bar for?  Is there any way I can hide it? 

Thanks

felis

In the line on top of the "bar" there is a button under frame 13.

It will turn yellow when you hoover your mouse over it. Click that.