code: public void removeCategoryParam(String key) {
  
          if (m_searchObject.getCategories().contains(key)) {
              m_handler.onClearCategories(Collections.singletonList(key));
              m_searchObject.removeCategory(key);
              updateResultsTab(false);
              ValueChangeEvent.fire(this, m_searchObject);
          }
      }
docs: Removes the category from the search object.<p>
  
  @param key the category