code: public void clearCategories() {
  
          List<String> selectedCategories = m_searchObject.getCategories();
          m_handler.onClearCategories(selectedCategories);
          m_searchObject.clearCategories();
          updateResultsTab(false);
          ValueChangeEvent.fire(this, m_searchObject);
      }
docs: Removes all selected categories from the search object.<p>