How to render a hidden window? - extjs

Question

I have an iframe (fit in a window) to load before showing it.
When I do :
window.show();
window.hide();
The window is not hidden. "window.show()" is used to render the iframe.
The loading of the iframe is about 10 sec.
How can I render the iframe without display the window?
My window :
var win = Ext.create('Ext.window.Window', {
height: '95%',
width: '95%',
modal: true,
header: false,
hideMode:'visibility',
constrain: true,
resizable:false,
itemId:'winIframeItemId....',
id:'winIframeId....',
baseCls: 'x-window-....',
layout: {
type: 'vbox',
align: 'stretch',
pack: 'start'
},
items: [{
xtype: 'container',
layout: {
type: 'hbox',
align: 'middle',
pack: 'end'
},
items: [{
xtype: 'button',
cls: 'x-button-close-window...',
height: 34,
width: 34
...
}]
}, {
xtype: 'container',
itemId:'conIframeWindow',
layout:"fit",
flex: 1,
items: [{
xtype: 'component',
autoScroll: true,
itemId:'IframeTest',
baseCls: 'x-component-w....',
autoEl: {
tag: "iframe",
domain: '....',
frameborder: 0,
src: url
}
}]
}]
});

Answer 1

Windows and menus are typically rendered to the document body. I was able to use the Ext.Component.renderTo configuration to render windows and menus without displaying them.
https://fiddle.sencha.com/#view/editor&fiddle/2f5h
// Render a hidden window.
var window = Ext.create('Ext.window.Window', {
renderTo: Ext.getBody(),
title: 'Window'
});
// Render a hidden menu.
var menu = Ext.create('Ext.button.Button', {
menu: {
items: [{
text: 'Item'
}],
renderTo: Ext.getBody()
},
text: 'Button'
});