How to hear all tracks when editing 1 instrument track

I have recorded 2 main tracks: (a group of) Drums + Keys. When I zoom in to the Key Editor to add notes to the Keys track, the drum tracks do not play, even though none of the drum tracks are muted. Oh no! I cannot hear any drum beat to accompany! I would like all tracks to play together - not just the one I am currently editing.

Any ideas how I can hear all tracks at once while editing one of them?

Most likely you have Solo Editor enabled - turn it off