Deleted Note can't be deleted

I deleted a Note. It's gone from the main Notes display (lists etc.) but its ghost, floating on top, keeps returning when I open Notes. Any time I try to kill the ghost (red button) the "beachball" comes up and I have to forcequit Notes. This only happens on my iMac. The synced version on MacBook and iPad are doing just fine. Any suggestion how to cure this?