Everyone on Windows (pretty much everyone) can you uninstall, make sure the Sigil directory in Program files has been deleted, reinstall then check if the issues still persist. I have reports from some users that this has fixed their issues with BV and disappearing text. One ever reported reinstall 0.4.2 over 0.4.905 and the issue persisting. I think there might be an issue with the Qt dlls not being installed properly when installing over an older version.
If this is the case I'll look into having the installer first uninstall the existing version if it's being installed to the same location.
@meme, are you using the binary installer? Did you also install over an existing install or is this with your source build? I Linux might be having the same issue as Windows.
@Zeypxi, Can you provide some sample text in French that is showing as misspelled that is correct. I want to be able to test any changes.
@theducks, Can you provide some sample text 3 or 4 matches for your regex (if uninstall and reinstall doesn't fix the issue for you). Again I want to be able to test and hopefully recreate the issue.
I thought of a problem with regex replace with the new find code. Not using the cache breaks replacements when using look ahead and behind expressions. I would rather not bring back the cache as the new code is quite a bit simpler but if I can't think of a fix I will. I should be able to do it with a smaller cache that only holds the last fine operation.
Another option I've been thinking about with replace is to have the replace button always replace the selected text even if it doesn't match the find expression. It would still move to the next find expression. How useful would it be to be able to select some text press replace and have the replacement expression used even if it doesn't match the find expression?
@meme, That error sounds like Xerces is having issues for some reason. Due to how little these files are used I'm not going to worry about it right now.
I apologize for all of my response being out of order. I'm party thinking out loud.