<zk>
	click "select 1" to select a navitem, clicking "unselect 1" should update the UI
	<navbar orient="vertical">
		<nav label="test" open="true">
			<navitem id="ni1" label="test1"/>
			<navitem id="ni2" label="test2"/>
		</nav>
	</navbar>
	
	<button onClick="ni1.setSelected(true)" label="select 1"/>
	<button onClick="ni1.setSelected(false)" label="unselect 1"/>
	<button onClick="ni2.setSelected(true)" label="select 2"/>
	<button onClick="ni2.setSelected(false)" label="unselect 2"/>
</zk>