Silly Question

On the far right of your screen, there's a grey line next to your center pane's scroll bar. Simply pull this to the left and the trigger/layer pane will reappear.

You can use this to resize the trigger/layer pane, and you probably just moved it by accident.

Jesse

Check to see if you moved the bar all the way to the right.

 and make sure the arrows are pointed down.

Jesse and Matthew, thank you both so much for your help! I had apparently moved something that closed the panel. I appreciate your help!!

Shari 

Thank you - this happened to me also and I was having trouble - I wasnt dragging it far enough left

Thanks so much!  I just did the same thing and wondered how to get it back.  :o)

Just wanted to say that this is not a silly question. I think this is the one question that every Storyline user asks.