How to remove and add tree node?

[GoogleCodeExporter]

1.How to expand the tree in program?not all expanded.

2.How to remove a tree node?
unselect() no effect

3.How to add a tree node?
on the TExtTreeTreePanel.Create,i can add a tree node.
But after the interface display,the user click a button to add a node,can 
not display,how to do?

4.How to select and highlight a tree node?
select() no effect

I found the extjs example code(Feed Viewer),but i don't know how to 
implement via ExtPascal.
Thanks.

Original issue reported on code.google.com by luoca...@gmail.com on 26 Jan 2010 at 7:42