Possible Clues:

• A bit of matter eponymously rejected in a stage performance
• Singing coming from a tree-top
• Show it's wrong to repeat
• Showboat or The Gondoliers, say
• Relative of a musical
• Work to repeat work
• Rate poet awful as provider of light entertainment
• Performance not quite open spoiled treat
• Arranged to repeat a theatrical production
• For music if it's a little light on show