Midi Track Turned Grey/Black and can not be edited

Can anyone help with the above problem? I was fast and furious editing in Piano Roll view when I notice I could not copy/paste any more. So I just continued and adding what I wanted manually. Not too bad.
Then when changing back to Track View my midi track had turned grey with a black top section.
It can also not be copy/pasted now
Did I hit some key/cmd while editing that could have done this?
 
Any help would be appreciated.
 
Barry