If I turn on conditional comments, default ext application throw syntax error
SCRIPT1004: Expected ';'
Easing.js?_dc=1350541991462, line 1
SCRIPT5022: The following classes are not declared even if their files have been loaded: 'Ext.fx.Easing'. Please check the source code of their corresponding files for possible typos: 'ext/src/fx/Easing.js ext-dev.js, line 9978
It happen because first line in Easing.js look like conditional directive and IE wrong interpret it
//@define Ext.fx.Easing <--- syntax error here
* @class Ext.fx.Easing