Unanswered: Different design for the Ext Window
There is any option or maybe something ready that will let me design the Ext Window in different way.
Maybe something like the jQuery dialog.
I search over the web and all the Ext window look the same.
You'll have to do some theming to get the window to look differently within whatever theme you are using (I assume you're using the default).
Check out the theming guid - http://docs.sencha.com/ext-js/4-1/#!/guide/theming
It's really quite easy to customize the appearance of ExtJS components, and the guide gives a good introduction to all the tools you'll need to do that.