How to adjust the Transition Graph in Animator view?

Something that's been bugging the hell out of me is that the Transition Graph (the line graph shown when you select a transition in the Animator view) just looks like a flat line in some animations I'm working with. As in, I keep seeing documentation showing a varying white line:



But all I'm seeing is a flat line. That looks like the vertical axis of the graph is way out of scale, so the vertical movements are too small to see at that scale.

Is there documentation saying what the controls are for the transition graph?

 

I'm having the same issue. It works fine at the beginning then suddenly at some point all the lines turn flat