Slight problem with some fixtures and fittings (6)
I believe the answer is:
lights
'some fixtures and fittings' is the definition.
(fittings in a room)
'slight problem' is the wordplay.
'problem' indicates an anagram.
'slight' anagrammed gives 'LIGHTS'.
'with' is the link.
(Other definitions for lights that I've seen before include "Windows" , "with something for the cat" , "Offal" , "Innards" , "Christmas tree adornments" .)