Locked swim lane header height

Hello,

I am trying to increase the height of a swim lane header. It seems to be locked. I can grab the bottom edge and drag it down, but when I let go, it snaps back to its original height.

I have a basic understanding of shape sheets. I set to 0 all the locking properties for this shape.

I wonder if a containing shape is locked.

Or, do you have any other ideas?

Many thanks.

Keith

R K Howard