Spellcheck not work...
You can count on it remaining broken until you do a better job detailing the problem and helping troubleshoot this issue that is seemingly unique to you.
Ok.
The use of 8-bit encoding, for example, Russian font, does not result in the selection of words, which is why the work of the CB fails.
I am afraid that someone, in spite to all Eastern Orthodox, does not want to use the key of compilation: -insignand-char, which is why the search for words begins to work with negative indices.
Thank you, that you are interested.