win: set NULL to focus_highlight.prev.target when it's deleted.
win: set NULL to focus_highlight.prev.target when it's deleted.

FlorentRevest/Elementary,tasn/elementary,rvandegrift/elementary,rvandegrift/elementary,FlorentRevest/Elementary,tasn/elementary,rvandegrift/elementary,tasn/elementary,tasn/elementary,tasn/elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,rvandegrift/elementary