show help message on map only when clicking a stop

app/src/main/java/com/rthoni/stssaguenay/ui/fragments/StopMapPickerFragment.java

         @Override
         protected void onClusterItemRendered(StopDboMapItem clusterItem, Marker marker) {
             _items.put(marker.getId(), clusterItem);
+            marker.setTag(clusterItem);
             super.onClusterItemRendered(clusterItem, marker);
         }
 
         _map.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
             @Override
             public boolean onMarkerClick(Marker marker) {
-                Toast.makeText(getContext(), R.string.stop_add_map_help, Toast.LENGTH_LONG).show();
+                if (marker.getTag() instanceof StopDboMapItem) {
+                    Toast.makeText(getContext(), R.string.stop_add_map_help, Toast.LENGTH_LONG).show();
+                }
                 return false;
             }
         });