Dwell on this issue? (5)
I believe the answer is:
brood
This clue is a double definition.
'dwell' is the first definition.
(I know that dwell can be written as brood)
'this issue?' is the second definition.
(thesaurus)
'on' is the link.
(Other definitions for brood that I've seen before include "Think anxiously for some time" , "Ponder mournfully" , "Offspring" , "Hatch" , "Meditate moodily" .)