Trill will not delete

An imported percussion part shows a trill for a rolled note. When I try to delete that trill (ornament?) Dorico does not delete it. How can I delete that trill (so that I can then replace it with slashes to show a proper roll)?

Thank you for your help.

I managed to fix this by deleting the note the trill was associated with, inserting a new note and dressing this appropriately.

When you’re able to attach files to your forum posts, it would be interesting to see the original file (e.g. the XML file or a Dorico project created by importing it, without subsequent changes) in order to check what was going on.