Code:
Ext.override(Ext.grid.GridView,{
refresh: Ext.grid.GridView.prototype.refresh.createSequence(function(){
		if(this.grid.autoHeight){
			var body = this.grid.el.select('.x-grid3-body').first();
			var height = this.grid.getGridEl().getHeight()-this.scroller.getHeight()+body.getHeight();
			this.grid.getGridEl().setHeight(height);
			this.scroller.setStyle({
				overflow: 'auto'
			});
			this.grid.autoHeight = false;
			this.layout();
			this.grid.autoHeight = true;
		}
	})
});