Very happy with story that's upset editor (6)
I believe the answer is:
elated
'very happy' is the definition.
(I've seen this in another clue)
'with story that's upset editor' is the wordplay.
'with' means one lot of letters go next to another.
'story' becomes 'tale' (synonyms).
'that's upset' says the letters should be written in reverse.
'editor' becomes 'ed' (abbreviation).
'tale' in reverse letter order is 'elat'.
'elat'+'ed' is 'ELATED'.
(Other definitions for elated that I've seen before include "Thrilled" , "Joyful, uplifted" , "Exhilarated, highly excited" , "Happy and exicited, overjoyed" , "Overjoyed, happy and excited" .)