Group audio events

I was editing some audio events, and I don’t know if I accidentally hit a shortcut, but it turns out that the audio events are in groups.
I did not use Ctrl + G and CTRL + U does not undo the group, because it is not the audio channel group, but the audio events.
Has anyone ever experienced this?
Thank you.

Could be folder group editing. Check the manual of your used software, if it has the feature.