Help tip on text field

[Qtx]

Ext.override(Ext.form.Field, {
    afterRender: Ext.form.Field.prototype.afterRender.createSequence(function(){
        if(this.qtip){
            var target = this.getTipTarget();
            if(typeof this.qtip == 'object'){
                Ext.QuickTips.register(Ext.apply({
                      target: target
                }, this.qtip));
            } else {
                target.dom.qtip = this.qtip;
            }
        }
    }),
    getTipTarget: function(){
        return this.el;
    }
});
Ext.override(Ext.form.Checkbox, {
    getTipTarget: function(){
        return this.imageEl;
    }
});

This works quite well, but I noticed that the tool tips on the fields disappear after resetting the form. How should the method reset be overridden to fix this problem?