Unable to Reduce Edit Page Track Height

So I suddenly seem to have a problem with the track height of only the first track (V1) as you can see in the attachment. I've tried reducing the track height, but all it does is reduce the height of the clips, but doesn't reduce the vertical height of the track between the top of the Audio Track and the bottom of the V1 clips ?

This is strange as it has been ok before, but when I tried doing a magic mask track in the colour page, then went back to the Edit page, I suddenly saw this.

You've probably got the Spline Editor open on a clip down the line.

Spline.png (5.72 KiB) Viewed 461 times

You've probably got the Spline Editor open on a clip down the line.

Spline.png

Oh, that's strange...so rendered out the project, came back to it around 30 mins later to have a look at the Spline suggestion ( FYI - I don't have a clue about 'spline', what it is etc), and noticed that the track height is fine now ?? I didn't do anything to do this? I didn't do anything other than to render the project ?...strange...but thanks for your suggestion and response Jim