The question Why most of the supersonic or fighter aircraft use all-moving control surfaces? emphasis the importance of all moving stabilator for supersonic aircraft.
Many supersonic aircrafts fitted with delta wings (Concorde, mirage III, mirage IV, saab draken, sr-71,...) rely on elevons only for pitch control and thus cannot use a all moving stabilator.
How do they overcome the reduced controllability due to the boundary separation of the airflow at the trailing edge of the wing?
My question is focused on aerodynamic solutions (I know some aircraft can shift there CG thanks to trim tank, and some fighter are not aerodynamically stable in pitch but I want to focus on the boundary separation issue).