These methods should not save reference to 'this', since that prevents doing

Code:
Ext.fly(someNode).fadeOut();
If this is intended (hopefully it's not), docs should state this. You get very bizarre and hard to debug errors from this, as some random element on the page will just disappear (when fadeOut is complete).

Code:
fadeOut: function(o) {
        var me = this;
        o = Ext.apply({
            opacity: 0,
            internalListeners: {
                afteranimate: function(anim){
                    var dom = me.dom;
                    if (dom && anim.to.opacity === 0) {
                        if (o.useDisplay) {
                            me.setDisplayed(false);
                        } else {
                            me.hide();
                        }
                    }         
                }
            }
        }, o);
        me.animate(o);
        return me;
    },