A major rumpus over little opens a traumatic problem (1,5,2,1,6)
I believe the answer is:
a storm in a teacup
'a major rumpus over little' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'opens a traumatic problem' is the wordplay.
'problem' is an anagram indicator.
'opens'+'a'+'traumatic'='opensatraumatic'
'opensatraumatic' is an anagram of 'A STORM IN A TEACUP'.
Can you help me to learn more?
(Other definitions for a storm in a teacup that I've seen before include "Much Ado about Nothing" , "too much for a trifle" .)