I did that anyway to try to better understand the interaction between Calibre and the device in regard to
my other issue, and this issue went away (as expected, now that I understand what's happening).
BTW, Kovid, I'd just like you to know that I really appreciate your responses; this level of communication between users and programmers is, sadly, rare, and all the more amazing considering that you don't charge money for the program. Thank you for all your effort.