test.zul

<window>
	<include id="inc" src="test2.zul" />
	<button label="change"
		onClick='self.previousSibling.src = "/hello.zul"' />
	<button label="remove" onClick="inc.detach()" />
</window>

test2.zul

<window>
	<div apply="TestComposer" />
	<button label="remove" onClick="self.previousSibling.detach()" />
</window>

TestComposer.java

public class TestComposer extends GenericForwardComposer {
	public void doAfterCompose(Component comp) throws Exception {
		super.doAfterCompose(comp);
		System.out.println("Init");
	}
	
	protected void finalize() throws Throwable {
		super.finalize();
		System.out.println("Finalize");
	}
}