Follow-up of 6c3aae8f89 -> Fixed update of objects list when object has a unique instance

src/slic3r/GUI/Plater.cpp

@@ -3113,7 +3113,8 @@ void Plater::priv::reload_from_disk()
             }
         }
 
-        sidebar->obj_list()->increase_object_instances(idx, object_orig->instances.size());
+        if (object_orig->instances.size() > 1)
+            sidebar->obj_list()->increase_object_instances(idx, object_orig->instances.size());
 
         // XXX: Restore more: layer_height_ranges, layer_height_profile (?)
     }