I am newbie, and about to make an analog to my current working alias ingestion from Viewport.js. So my Viewport.js is something like this:
... xtype: 'loginPanel'...

if the loginPanel.js (under view) is a panel or field container everything works fine, but not nice for a login window.

The panel one:
extend: 'Ext.panel.Panel',
alias: 'widget.loginPanel',
layout: {
type: 'vbox', // Arrange child items vertically
align: 'stretch', // Each takes up full width
padding: 5
height: 200,
width: 400,

And the window what is not doing:
Ext.define('myApp.view.loginPanel', {
extend : 'Ext.window.Window',
alias: 'widget.loginPanel',
title: 'Mywindow',
closeAction: 'hide',
width: 300,
height: 300,
layout: 'fit',
resizable: false,
draggable: true,
modal: true,

I hope you can help me, what I am doing wrong here. I have tried to explicit importing window.Window by required directive - just to be on a safer side. No luck. But I am still got the feeling it is related to xtype:'window'.