The head of the family

Refer to the Header.js file:

// app/view/header/Header.js
Ext.define('Postcard.view.header.Header', {
    extend: 'Ext.Toolbar',
    requires: ['Postcard.view.header.HomeButton'],
    xtype: 'app-header',
    height: 60,
    controller: 'header',
    viewModel: 'header',
    session: true,
    items: [
        { 
            xtype: 'home-button', cls: 'title', html: 'Postcard',
            bind: { hidden: '{menuButton.pressed}' }
        },
        {
            xtype: 'tbspacer',
            bind: { hidden: '{menuButton.pressed}' } },
        { 
            xtype: 'textfield', flex: 1,
            cls: 'search-box', emptyText: 'Search', 
            bind: '{searchTerm}',
            plugins: ['responsive'],
            responsiveConfig: {
                'tall': { 
                    hidden: true,
                    bind: { hidden: '{!menuButton.pressed}' }
                }, 
                'wide': { hidden: false } 
            }
        },
        { 
       ...