Right for salesman to be on the counter (6)
I believe the answer is:
proper
'right' is the definition.
(I know that proper can be written as proper)
'for salesman to be on the counter' is the wordplay.
'for' becomes 'pro' (as in being 'pro' or in favour of something).
'salesman' becomes 'rep' (sales rep).
'to be on the counter' is a reversal indicator (counter can mean in the opposite direction).
'rep' back-to-front is 'per'.
'pro'+'per'='PROPER'
(Other definitions for proper that I've seen before include "Genuine; suitable" , "Befitting" , "Correct; formal" , "Genuine; part of church service" , "Correct in behaviour" .)