Vertical gaps in timeline between audio and video rows

DR 18.6 Mac: The controls to change the vertical positioning of the audio and video rows in the timeline is very confusing to this new user. I've managed to get the audio "row" to the bottom of the screen. And I can scroll V1 so that it is stacked on top of A1 (though it is too easy to accidentally move it up or down out of position. But to then get V2 stacked right over V1 is a problem. Sometimes it just happens and I have no idea what triggered it. But as soon as I feel relief, V2 changes to have a big gap between it and V1; thus, I am unable to see all 3 at once. I have tried combinations of dragging the "lines" between them that are active. I have googled madly trying to find the solution, but I am obviously not coming up with the needed search strings. It would be soooo nice if I could just grab and drop the rows into the desired positions and "lock" them in place. Can anybody tell me the secret to success? Thank you!

Have you by any chance clicked on the keyframe icon which will create a gap between tracks?

Keyframe selection.jpg (161.71 KiB) Viewed 662 times

If you haven't already, might I suggest you have a look at the extensive free training materials supplied by Blackmagic. You will find them here.
https://www.blackmagicdesign.com/uk/pro ... e/training
There is also the Resolve Reference Manual which you will find as the first entry in the Resolve Help dropdown menu.

You can lock a whole track.