enable LoadMask for Extjs4.1

gistfile1.js

Ext.define("Ext.view.AbstractView.LoadMask", {
    override: "Ext.view.AbstractView",
    onRender: function() { 
        this.callParent(); 
        if (this.loadMask && Ext.isObject(this.store)) { 
            this.setMaskBind(this.store); 
        } 
    } 
});