Collapse multiple lines in Dope Sheet?

Apologies if this is obvious or has been answered before - I tried searching but perhaps couldn’t think of the right keywords.

Is there a way to collapse multiple lines in a Dope Sheet? I don’t mean ‘collapse all’ into a one line summary. I mean so it’s easier to browse your way through if you have hundreds of objects with actions.

Many thanks

A simple tap on + and - keys on the keyboard can do this for you