Have a lot of layers in your timeline? Of course you do, you're smart and talented enough to be reading this advanced book. Wouldn't it be nice to make a little more room in your timeline to see things? Harness the Shy layers feature to dramatically cut down on vertical scrolling.
To designate a layer as shy, click on the little "Kilroy" icon on each layer you want to hide.
At the top of the timeline click the Shy (Kilroy) icon.
All shy layers will disappear from the timeline view. They will, however, continue to affect the composition, and their results will show up in the Comp Window.
At any time, you can reveal all shy layers by clicking on the Shy icon at the top of the timeline.