Iam facing issue in Mozilla, Chrome

I have created one js file. In that i created window with one button. inside widow items, i gave panel. Using Ext.get("panelid").load({url:url,scripts:true}); i rendered panel inside window. After that i'm hiding window and again i'm showing window. In such situation window is showing but buttons such as minimize,close are not showing.

Please help me as soon as possible.