Reduce a layer
It is also possible to reduce the layers to better organize ourselves. It is practical when there are too many of them to be displayed on the screen.
A left click on one of the buttons in the red circle on the below screenshot reduces the size of a layer in the Timeline.
The - button changes and becomes a + button. Click on + to increase it again.
The layer itself is not changed in any way. You still can work on it.
Only its name, global opacity and the five options nearby are available in the timeline.