In the dress trade, but not all the rage (3)
I believe the answer is:
rag
'in the dress trade' is the definition.
I can't judge whether this definition defines the answer.
'not all the rage' is the wordplay.
'not all' means to remove the last letter (not quite all of it).
'rage' with its last letter taken away is 'RAG'.
'but' is the link.
Can you help me to learn more?
(Other definitions for rag that I've seen before include "Duster, perhaps" , "charity event" , "Ridicule" , "Small piece of cloth and university week" , "Piece of cloth and student fun" .)