I am using faclets and I have tried this:
<ui:debug hotkey="P" rendered="true"/>
which will popup a faclets debug page when I press CTRL-ALT-P in the browser.
In this page I can view the scoped variables, but when I click the Component Tree
I only get a javascript error:
faceletstoggle is not defined onclick(click clientX=0, clientY=0)
It's a bug
https://facelets.dev.java.net/issues/show_bug.cgi?id=292