Piece of glass left in compartment (5)
I believe the answer is:
panel
'compartment' is the definition.
'piece of glass left' is the wordplay.
'piece of glass' becomes 'pane'.
'left' becomes 'l' (common abbreviation).
'pane'+'l'='PANEL'
'in' acts as a link.
(Other definitions for panel that I've seen before include "a selection of which is put in box" , "Wall mounting" , "Judging committee" , "Jury members" , "that's sometimes beaten?" .)