Sometimes when I import multiple formats of a book into my library, Calibre won't recognize one of them due to metadata (generally the PDFs). However, in the past I was able to just drag the unrecognized one to the recognized one and Calibre would merge them without issue. Currently, I get a little denied symbol (circle with line through it) on my cursor when I attempt to do what used to work just fine.
This is on 6.17 running in Ubuntu 23.04.
Any idea what I'm doing wrong?
