Window dressing all over? (8)
I believe the answer is:
curtains
This clue is a double definition.
'window dressing' is the first definition.
(curtains cover a window)
'all over?' is the second definition.
('it's curtains' can mean it's all over)
(Other definitions for curtains that I've seen before include "Window hangings" , "I run cats up the drapes" , "Hanging drapes" , "Draperies" , "theatre equipment!" .)