Like I wrote to the specific Extention's thread,
this ux, with Extjs3.0.0, has a problem...
I explained it to the post linked below
with Ext3.0 Rc2 it works fine... some idea about causes??
thanks for any hints.
Sencha - Community Support Team
Generally, it's up to the authors to provide support for their extensions or plugins. Either way, you can step through the code and see what is going on if you have the time. use ext-all-debug.js