Does not work with flac files

I have just downloaded MP3TAG, having previously used "Stamp" for mp3 and flac files, but finding it a little buggy and prone to crashing.
MP3TAG seems to operate correctly with mp3 files, but will not recognise flac files.

FLAC Frontend is loaded on my system and "Stamp" ID3 works OK with flac files, so the problem does seem to be with MP3TAG.

Does anyone have any suggestions?

Oops! Just noticed that the folders I was selecting have had the flac files deleted. I'll be more careful next time!