Steps to reproduce

1. run attached zul and java under 8.0.0.FL.20150722-Eval
2. click first navitem, the content area displays the menu label.
3. switch to "Menu hierarchy 2"
4. click first navitem

Actual result

a javascript error showed.

Uncaught TypeError: Cannot read property 'bindLevel' of nullzkmax.nav.Navbar.zk.$extends.closeNav @ zkmax.nav.wpd:5zkmax.nav.Navbar.zk.$extends.setSelectedItem @ zkmax.nav.wpd:5zkmax.nav.Navitem.zk.$extends.doSelect_ @ zkmax.nav.wpd:8f @ zk.wpd:21(anonymous function) @ zk.wpd:21bH.event.dispatch @ zk.wpd:9bH.event.add.cb.handle @ zk.wpd:9

Expected result

show navitem's label