Fixed new trouble with editor (6)
I believe the answer is:
nailed
'fixed' is the definition.
(I've seen this before)
'new trouble with editor' is the wordplay.
'new' becomes 'n' (abbreviation as in New Testament NT).
'trouble' becomes 'ail' (synonyms).
'with' means one lot of letters go next to another.
'editor' becomes 'ed' (abbreviation).
'n'+'ail'+'ed'='NAILED'
(Other definitions for nailed that I've seen before include "Hammered in" , "Hit precisely" , "Fastened with metal pin" , "Playful teasing remarks" , "snatched" .)