var win;

function popup(title, width, height, url) {
     win = new Ext.Window({
               title: title,
               layout:'fit',
               width: width,
               height: height,
               plain: true,
               modal: true,
               items: [{
                   xtype: 'iframepanel',
                   closable: false,
                   frameBorder: 0, 
                   cls:'x-panel-body',
                   defaultSrc: url
               }]
           });
    win.show();
}

function refresh() {
    if (win != null) {
        win.hide();
    }
    var tab = Ext.getCmp('TABS').getActiveTab();
    tab.setSrc(tab.url);
}