the theatre mode plugin works off a hard-coded set of names
"artist"
"title"
"trackartistandtitle"
"album"
"albumandyear"
"albumartist"
"bpm"
"composer"
"comment"
"conductor"
"custom1".."custom16"
"discno"
"disccount"
"discandtrackno"
"duration"
"genre"
"genrecategory"
"grouping"
"kind"
"mood"
"occasion"
"playcount"
"publisher"
"quality"
"rating"
"ratingalbum"
"ratinglove"
"speaker"
"skipcount"
"tempo"
"trackno"
"trackcount"
"language"
"work"
"showmovement"
"movement"
"movementno"
"originalartist"
"originaltitle", "originalalbum"
"originalyear"
"instrumentsperformers"
"virtual1".."virtual25" (will add the missing ones)
"year"
"year(yyyy)", "year (yyyy)"
"#"