@SuppressWarnings("unused")
  public void scheduleItemUpdate(@NotNull LookupElement item) {
    // this check significantly affects perfomance with enabled assertions
    if (LOG.isTraceEnabled()){
      LOG.assertTrue(getItems().contains(item), "Item isn't present in lookup");
    }
    cellRenderer.updateItemPresentation(item);
  }
@SuppressWarnings("unused")
  public void scheduleItemUpdate(@NotNull LookupElement item)