Originally Posted by Manichean
Actually, this seems to be a reproducible behaviour. Regardless of where I (single-)click to select a book (or whether I select it via keyboard), whenever I press the delete button, either the title or the field I clicked on to select gets deleted and goes into edit mode. It's never bothered me, but I've noticed it.
EDIT to add: XP SP3, Calibre 0.7.18
I use XP SP3, Calibre 0.7.18 and Regardless of where I (single-)click to select a book (or whether I select it via keyboard), whenever I press the delete button the "Are You Sure" window pops up verifying I want to delete the book. I can't get it to do anything but delete the book. I wonder what is different between our preferences?
I can also recreate your experience by selecting any book and clicking any key that is not a shortcut. I think this is your reproducible delete field, But hitting the delete key always deletes the book.