@Override
  public void loadState(@NotNull Element state) {
    myClass2Properties.clear();
    myClassName2Item.clear();
    myGroups.clear();

    processGroups(state.getChildren(ELEMENT_GROUP));

    // Ensure that all predefined items are loaded
    LOG.assertTrue(myPanelItem != null);

    if (!state.getAttributeValue(ATTRIBUTE_VERSION, "1").equals("2")) {
      upgradePalette();
    }
  }
@Override
  public void loadState(@NotNull Element state)