Something Joanna has, displeasing Aunt Dotty (10,5)

I believe the answer is:

sustaining pedal

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'something joanna' is the definition.
I can't judge whether this defines the answer.

'displeasing aunt dotty' is the wordplay.
'dotty' is an anagram indicator (a mad or 'dotty' version of the letters).
'displeasing'+'aunt'='displeasingaunt'
'displeasingaunt' is an anagram of 'SUSTAINING PEDAL'.

'has' is the link.

Can you help me to learn more?

I've seen this clue in The Telegraph.

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