Regrets upsetting the user (4)

I believe the answer is:

rues

'regrets' is the definition.
(I've seen this before)

'upsetting the user' is the wordplay.
'upsetting' indicates an anagram.
'user' is an anagram of 'RUES'.

(Other definitions for rues that I've seen before include "Is sorry for - plants" , "Bemoans" , "Regrets, to be sure" .)

I've seen this clue in the Evening Standard.

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