Lock icon appeared on a few comps (!) WHY?

Sorry to post this here guys… I looked thru the Comp Tool section in the Operation manual but couldn’t find the answer.
While comping on the various lanes (using the Comp Tool), I must have accidentally hit some sort of key combination because I now have a padlock icon on 2 of the comps (on the same lane). I don’t see any lock/unlock tool so I’m not sure what happened and how to remove the lock.

Can someone provide some quick assistance please?

You can use CTRL+SHIFT+L to lock parts and CTRL+SHIFT+U to unlock them.

Awesome! Will this prevent me from creating the perfect part when I’ve selected all the sections I want with the Comp Tool? Or does it just lock their “timing” in the timeline?