@pipcat, surquizu
I'm still on FW 3.19.5613. I can confirm the original patch, as shown in post #1, works fine for me.
Great work, guys, karma coming your way
.
I've been able to move all my non-Kobo Eng-Eng dictionaries into Extras instead of pseudo-renaming them to masquerade as the (unused by me) monolingual German, French etc default dictionaries. Hopefully this will mean that, on the rare occasion when I let Kobo Desktop sync my devices, it won't keep overwriting them with the official versions.
Just for fun (
I really need to get out more!) I also created from scratch a small extra dictionary from the terms found in the Glossaries of the first 2 books in the Robert Jordan Wheel of Time series. The dictionary pop-ups are certainly more convenient than having to constantly turn to the Glossary at the back of the book. There are some limitations, because I don't think there's a way of looking up multiple words as a phrase. I had to work round it by adding 2 entries for 2-word terms, etc. Only time will tell whether it was worth the manual effort involved in creating the dictionary contents.