Do not break the dependency chain when activating gravity tasks if cooling is on.

src/cell.c

@@ -2493,6 +2493,8 @@ int cell_unskip_gravity_tasks(struct cell *c, struct scheduler *s) {
     if (c->kick2 != NULL) scheduler_activate(s, c->kick2);
     if (c->timestep != NULL) scheduler_activate(s, c->timestep);
     if (c->end_force != NULL) scheduler_activate(s, c->end_force);
+    if ((e->policy & engine_policy_cooling) && c->cooling != NULL)
+      scheduler_activate(s, c->cooling);
     if (c->grav_down != NULL) scheduler_activate(s, c->grav_down);
     if (c->grav_down_in != NULL) scheduler_activate(s, c->grav_down_in);
     if (c->grav_mesh != NULL) scheduler_activate(s, c->grav_mesh);

src/engine.c

@@ -3774,8 +3774,9 @@ void engine_marktasks_mapper(void *map_data, int num_elements,
     }
 
     /* Subgrid tasks */
-    else if (t_type == task_type_cooling || t_type == task_type_sourceterms) {
-      if (cell_is_active_hydro(t->ci, e)) scheduler_activate(s, t);
+    else if (t_type == task_type_cooling) {
+      if (cell_is_active_hydro(t->ci, e) || cell_is_active_gravity(t->ci, e))
+        scheduler_activate(s, t);
     }
   }
 }