JPAContainer and a hierarchical display NativeSelect (suggest: sort problem

Hello @all,

iam struggeling aroung for a few days, and i did not found any solution for my problem.

Iam using a Tree to display and manage some hierarchical data. I set an jpaContainer as dataSource to it, to manage my beans. Now i want to sort that jpaContainer items by the parent, to display them in a Native Select like:

-Parent 1
--Child 1 of Parent 1
--Child 2 of Parent 1
-Parent 2
--Child 1 of Parent 2
-Parent 3

...and so on. Iam trying to sort them with a nested property, shown in attachment 1 (this is my JPAContainer).

My Entity is shown in attachment 2.

In attachment 3 you can see how i "start" the sort.

What am i doing wrong? It seems to be, that the sort did not work. When i open the window where my NativeSelect is shown, the items are still displayed in order they were added to my tree and not in the order i wrote before. What should i do to reach it?