I put some text into a work item's Notes field specifically to get it returnable by Search, as I think I've read help pages that say Search checks through Name, Description (Objective?) and Notes.
The Search mechanism that launches from top-right, next to my user picture, now returns that work item.
But the Work Views screen does not return it.
This is potentially a worry because discovering the ability to use Work Views for 'advanced' searches has been the most exciting thing to happen to me for ages. I want to live and breathe with searches for existing unclosed Defects, and this is the most user-friendly approach to it I've been able to find.