According to the docs, for Ext.Component:


maxHeight : Number
The maximum value in pixels which this Component will set its height to.

Warning: This will override any size management applied by layout managers.


maxWidth : Number
The maximum value in pixels which this Component will set its width to.

Warning: This will override any size management applied by layout managers.

(etc.)

However, near as I can tell they don't actually ever get used. The only reference I could find in any of the actual 1.0.1a code is:
Code:
    adjustScale : function(){
        Ext.apply(this,{
            maxWidth : window.innerWidth,
            maxHeight : window.innerHeight,
            minWidth : window.innerWidth * .5,
            minHeight : window.innerHeight * .5
        });
    },
in MessageBox.js. I think it's just ignored everywhere else. Am I missing something?