Problem with Ghost surface

I was trying to trim a surface and after ctl-z and a few ops, I ended up with this (right-side, inside hull). The surface cannot be selected, untrimmed itself and cannot be deleted. I saved and restarted Rhino, still there. It is in a layer which I can hide or show.
I did selbadobjects to no avail.
Any clue?

I suspect if you run SelBadObjects that will select.
Use ExtractBadSrf to pull the problem surface out of the polysurface.
UnTrim the surface keeping the curve, then retrim it and Join it back up.
I’d suggest running with CheckNewObjects turned on so you are aware of bad objects when they are created.
Here’s a link to the KB FAQ about them:

Good luck

Worked, thanks. I had run SelBadObjects but nothing highlighted, so assumed it didn’t work but now when I ran it again, even though it didn’t highlight, the surface was indeed picked. I deleted it and it’s fixed.
Mucho thanks.