Worked out, when one had been put in the shade (8)
I believe the answer is:
reasoned
'worked out' is the definition.
(I've seen this in another clue)
'when one had been put in the shade' is the wordplay.
'when' becomes 'e' (I've seen this in other clues).
'one had' says to put letters next to each other.
'been' becomes 'ason' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'put in' is an insertion indicator (back).
'the shade' becomes 'red' (red is a colour or shade).
'e'+'ason'='eason'
'eason' inserted inside 'red' is 'REASONED'.
Can you help me to learn more?
(Other definitions for reasoned that I've seen before include "Well thought out" , "made a logical case" , "Deduced or concluded" , "Argued logically" , "Debated in calm and logical way" .)