Diminutive dish in sad film (6)
I believe the answer is:
weepie
'sad film' is the definition.
'diminutive dish' is the wordplay.
'diminutive' becomes 'wee' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'dish' becomes 'pie' (I've seen this before).
'wee'+'pie'='WEEPIE'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for weepie that I've seen before include "sloppy work" , "Novel type" , "Love Story, among many" , "Film that makes you cry" , "Sentimental film (colloq.)" .)