Mark geoshapes as interactive if there are selections present in

other models as geoshapes are likely to be background layer.

src/compile/mark/mark.ts

@@ -376,7 +376,7 @@ function interactiveFlag(model: UnitModel) {
   }
   return parentCount
     ? {
-        interactive: unitCount > 0 || !!model.encoding.tooltip
+        interactive: unitCount > 0 || model.mark === 'geoshape' || !!model.encoding.tooltip
       }
     : null;
 }