All over the place, in the main (2,3)
I believe the answer is:
at sea
This clue is a double definition.
'all over the place' is the first definition.
(I've seen this before)
'in the main' is the second definition.
(I've seen this before)
(Other definitions for at sea that I've seen before include "Lost or confused - on the briny?" , "Might marines be" , "Thrown" , "Where Corcoran was hardly ever sick" , "on board" .)