How to undo split video tracks (not clips)?

Hello!
I'm fairly new to using Davinci Resolve 16 and it seems that I misclicked somewhere and now my video track 1 is split into 2 parts: the top one with the actual video clips, the lower one is empty. I can't do anything with this lower one and I would like to remove it but don't know how. Does anybody know how to do that? Dragging the track up/down to increase/decrease the size doesn't change anything. In the attached screenshot you can see the difference between the first and second video tracks.
Thanks a lot in advance!

You have the Keyframe Editor open on a clip somewhere. The black diamond to the right of the white icon.

Spline.png (5.72 KiB) Viewed 1764 times

Thanks a lot! I actually saw it myself later on.. I really don't know how I missed that, I was sure I actually went through the entire timeline and didn't see anything open. I felt like an idiot once I saw it, this cost me probably around half an hour going through all the settings to see if I had changed something somewhere....
Thanks again for the answer, I really appreciate it!! All the best and have a nice day