Deleting part of a single track when there are multiple

I’m confused by the newer versions of Audacity. I’m trying to highlight and delete a part of a track and it is deleting that time section on every track I have open, with the clock sign coming up over them. I don’t know what this means or how to stop it, please help.

You have accidentally enabled “Sync-Lock”.
Which exact version of Audacity do you have (look in “Help > About Audacity”)