I wanted to share a really cool tool that my colleague released just today. It's called App Inspector for Sencha and it's a Chrome extension that fans of FireFox' Illuminations for Developers will recognize instantly.
It's the first release, so functionality is limited, but it does have some very useful features already. Particularly, being able to pin-point an ExtJS component when browsing DOM:
Also, it lets you browse the ExtJS component tree in general:
As far as I could tell, it doesn't work for Sencha Touch yet, but I hope that will be added soon.