private void migrateShowFlattenSetting() {
    PropertiesComponent properties = PropertiesComponent.getInstance(myProject);

    if (properties.isValueSet(FLATTEN_OPTION_KEY)) {
      properties.setList(GROUPING_KEYS, properties.isTrueValue(FLATTEN_OPTION_KEY) ? Collections.emptyList() : DEFAULT_GROUPING_KEYS);
      properties.unsetValue(FLATTEN_OPTION_KEY);
    }
  }
private void migrateShowFlattenSetting()