Highlighting a PDF within a project in Scrivener 3

I’ve got an important PDF in the main project I’m working on, and would like to highlight a phrase in it. But it won’t let me do it - the text editing boxes are greyed out. Now, this PDF survives from the earlier version of Scrivener, and has plenty of phrases highlighted from that time.

What’s wrong, and can I fix it?

Anyone?

You do this exactly the same as you did in Scrivener 2 - select some text in the PDF and hit Shift-Cmd-H or go to Format > Highlight > Highlight Text. You cannot use the formatting bar above the editor because that is for text only and cannot affect PDF files (the same as in Scrivener 2).

Hope that helps.

All the best,
Keith

Thanks, KB, that worked.