public procedure problem

hi all, i have two form. first form has treeview control and one public procedure( load data from database ). second form.showdiaglog(this) in second form,including insert or update functions. And then call first form( his parent ) procedure( load data from database ). but treeview control where in first form is not refresh. so, i try to solve these problem by trace method. then i discover treeview is refresh. (if not use trace, it not refresh) why? ps: i solve these problem another way.