Smart view and tags

[a2534838]

I tag all my files with MusicBrainz Picard and the last.fm plug in
and as my collection grows it gets harder to find the right stuff so I want to use smart views but it's not working with the fields I want to use

some examples which are not working

code:
grouping HAS "metal"

mood HAS "melancholic"

releasetype == "album"

this will

code:
genre HAS "metal"

but there is no real difference except the field names
and there it should be possible to use any tag field a file has