You can mark a layer as shy and then use the Hide Shy Layers composition switch at the top of the Timeline panel to hide all shy layers in the Timeline panel layer outline. Making layers shy is useful for making room in the Timeline panel to show the layers and layer properties that you want to adjust.

The icon in the Switches column indicates whether a layer is shy  or not shy .

Shy layers are still rendered, both for previews and for final output. To exclude layers from previews or final output, use the Video switch or make the layer a guide layer.