selecting in one track only

Using Windows 10 and version 2.1.1
I cannot figure out how to select and delete portions of a given track without also affecting other tracks. Manual not much help. When I attempt to select a portion of a track for deletion, the corresponding range in other tracks becomes highlighted with little images of clocks. Never saw this before, and don’t know what’s going on. Ideas???

Somehow you selected Tracks > Sync Lock Tracks.


see this page in the Manual:

The button is in the Edit Toolbar: