Devexpress TreeList等一段时间展开就会很卡

public frmMyUser()
{
	InitializeComponent();
	// 如果不添加 这两个事件，打开几个窗体后，TreeList 展开节点就会很慢很慢
	this.tree_Module.BeforeExpand += Tree_Module_BeforeExpand;
	this.tree_Module.AfterExpand += Tree_Module_AfterExpand;
}
private void Tree_Module_BeforeExpand(object sender, DevExpress.XtraTreeList.BeforeExpandEventArgs e)
{
}
private void Tree_Module_AfterExpand(object sender, DevExpress.XtraTreeList.NodeEventArgs e)
{	
}