I have a txt-file with mixed cyrillic/english text in ANSI encoding. In MDV if I search for cyrillic word, nothing is found. Case dosen't matter. I basically copy some cyrillic text, paste it in the Find field, press Enter and get "No more found". Search for english text works OK.
If I open this file in Windows Notepad, search for cyrillic text works fine. If in Notepad I save this file as UTF-8 or UTF-16, then in MultiDataViewer search works, but only if case matches, so e.g. search for "станислав" can't find "Станислав" even with disabled [Match case] option.