<%@page contentType="text/html;charset=UTF-8" language="java"%> This example uses a frameset and a couple of frames. In the left frame is a Tree where a selection event will populate the right frame. The tree can be expanded an collapsed. The way this works is that the target of the The treeItems set an href and a target of the other frame. The tree must set a different action and a target of the containing frame for the expansion target.