Now that Ext.Loader is working correctly, I've noticed that none of the scripts loaded dynamically by Ext.Loader show up in the Scripts tab in Firebug - which defeats one of the main reasons for loading individual files instead of ext-all.js - reading the files and setting breakpoints easily. I've checked FF 3.6.16 with Firebug 1.6 and FF 4 with Firebug 1.7.

They show up in Chrome, but the awesome Illuminations plug-in is Firebug-specific (AFAIK).

This is a major bummer, unless there is a work-around.