code: public boolean isClientWindowRenderModeEnabled(FacesContext context) {
          boolean result = false;
          Map<Object, Object> attrMap = context.getAttributes();
          result = !attrMap.containsKey(PER_USE_CLIENT_WINDOW_URL_QUERY_PARAMETER_DISABLED_KEY);
          return result;
      }
docs: <p class="changed_added_2_2">Methods that append the ClientWindow to generated
  URLs must call this method to see if they are permitted to do so.  If
  {@link #CLIENT_WINDOW_MODE_PARAM_NAME} is "url" without the quotes, all generated
  URLs that cause a GET request must append the ClientWindow by default.
  This is specified as a static method because callsites need to access it
  without having access to an actual {@code ClientWindow} instance.</p>
  
  @param context the {@link FacesContext} for this request.
  
  @since 2.2