Updating layer states
For example, if you solo a video layer, any lights and audio layers are unaffected, so they appear when you preview or render the composition. is dimmed for other layers when a layer is soloed, indicating that the other layers are not visible.
Lloyd Alvarez provides a script on his After Effects Scripts website with which you can tag layers and then select, shy, and solo layers according to their tags.
You can filter layers in the Timeline panel to show only layers with properties that match a search string or certain other characteristics.
See Search and filter in the Timeline, Project, and Effects & Presets panels and Showing properties and groups in the Timeline panel (keyboard shortcuts).
When a layer is locked, you cannot select it in either the Composition or Timeline panels.