@Kovid
Thank you for finding the reason!! I was sure something had changed with version 4 but was totally out of my mind as to the reason...
I did not suspect it because I have been using nnbsp in my epubs
for many years. Does this mean that from now on, I'll have a choice:
- either use nnbsp (authorized and even recommended by French punctuation rules)
- or use Calibre French spellchecker?
The updated ICU library made indeed a strange choice. Can this absurd situation be normalized to revert to the customary way? (i.e. to use nnbsp AND to use spellcheck)