Hi
With the new version of Sigil 0.7.3 (Linux 64 bits compiled by DiapDealer), I can use normally nbsp like it was before, for example for version 0.5.3. They are no more lost on opening and this is very good.
However, I failed to insert nnbsp (either in &#_x202f or &#_8239; forms - without the _ of course) in an EPUB. When I saved and opened the EPUB they were gone and replaced by a white space.
Up to now, I cannot point this problem squarely to Sigil and I still have some checks to do. I hope to be able to post a test EPUB soon. This is because with ADE 2.0, I experiment also some other unexplained problems: the text-indent is forgotten, and a space between paragraphs has been added without any code for it in the CSS. So, there could be some other murky things going on...