Search filmroll does not update collection

In DT git master there are some gui glitches in the collections lib.
To reproduce:

1. Import a few film rolls
2. with DT closed, rename on purpose the folder of one film roll
3. Open DT, the renamed film roll is shown in the collections lib with a strikethrough
4. Right-click on the film roll and select "search film roll..."
5. Select the renamed folder

Expected behavior: according to the code in view_popup_menu_onSearchFilmroll()

      /* reset filter so that view isn't empty */
      dt_view_filter_reset(darktable.view_manager, FALSE);

      /* update collection to view missing filmroll */
      _lib_folders_update_collection(new_path);

      DT_DEBUG_CONTROL_SIGNAL_RAISE(darktable.signals, DT_SIGNAL_FILMROLLS_CHANGED);

The filmroll name in the treeview should no longer be strikethrough. The collection should not be empty, the found film roll should be visualized.

Observed behavior: The filmroll name is still strikethrough and stays so until a DT restart. The collection is empty. The lib reset button does not work until one of the filmrolls is selected with a double click

EDIT: by the above code calls _lib_folders_update_collection(new_path); but new_path is never used inside the function.