private void readGroup(Element groupElement, ProductivityFeaturesProvider provider) {
    GroupDescriptor groupDescriptor = new GroupDescriptor();
    groupDescriptor.readExternal(groupElement);
    String groupId = groupDescriptor.getId();
    myGroups.putIfAbsent(groupId, groupDescriptor);  // do not allow to override groups
    readFeatures(groupElement, groupDescriptor, provider);
  }
private void readGroup(Element groupElement, ProductivityFeaturesProvider provider)