Enable loadmask Iframe while processing

how to set a loadmask for an Iframe while generating a pdf report

Code:

onBtnImprimirClick: function(button, e, eOpts) {        
        var Iframepanel=Ext.create('Ext.ux.IFrame', {
        extend: 'Ext.Component',
        alias: 'widget.uxiframe',
        loadMask: 'Creating report...please wait! ',        
        src:'pdf.php',   
            
    });  
        var WinReporte=Ext.create('Ext.Window', {
            title: 'Reporte de Clientes',
            width: 750,
            height: 400,
            layout: 'fit',
            xtype: 'panel',
            modal:true,
            items: Iframepanel
            LoadMask: true
        }); 

       WinReporte.show();
    } ,

I've set loadmask to true, but didn't work!

Is there anything glaringly wrong here?

thanks



Enable loadmask Iframe while processing