VERY SLOW behavior of fields in nested panels (compared to extjs 3)

[tprodigy1]

here is an exemple to show how SLOW can behave extjs 4 (the same type of code is IMMEDIATE in extjs3)

in the code below, I create 4 comboboxes that I put in multiple nested panels (7 levels of nested panels)
complex applications can easily reach this number of nested panels
selecting an element in the first combo, will show / hide the others. this operation can take several seconds even with chrome, it's crazy.

Ext.onReady(function() {
    Ext.tip.QuickTipManager.init();

    // Store creation
    Ext.define('State', {
        extend: 'Ext.data.Model',
        fields: [
            {type: 'string', name: 'abbr'},
            {type: 'string', name: 'name'},
            {type: 'string', name: 'slogan'}
        ]
    });

    // The data for all states
    var states = [
        {"abbr":"AL","name":"Alabama","slogan":"The Heart of Dixie"},
        {"abbr":"AK","name":"Alaska","slogan":"The Land of the Midnight Sun"},
        {"abbr":"AZ","name":"Arizona","slogan":"The Grand Canyon State"},
        {"abbr":"AR","name":"Arkansas","slogan":"The Natural State"}];

    var store = Ext.create('Ext.data.Store', {
        model: 'State',
        data: states
    });
    
    // a Combobox
    var simpleCombo2 = Ext.create('Ext.form.field.ComboBox', {
        fieldLabel: 'combo2',
        displayField: 'name',
        width: 320,
        labelWidth: 130,
        store: store,
        queryMode: 'local',
        typeAhead: false,
        forceSelection: true,
        allowBlank : false
    });

    // a Combobox        
    var simpleCombo3 = Ext.create('Ext.form.field.ComboBox', {
        fieldLabel: 'combo3',
        displayField: 'name',
        width: 320,
        labelWidth: 130,
        store: store,
        queryMode: 'local',
        typeAhead: false,
        forceSelection: true,
        allowBlank : false
    });

    // a Combobox            
    var simpleCombo4 = Ext.create('Ext.form.field.ComboBox', {
        fieldLabel: 'combo4',
        displayField: 'name',
        width: 320,
        labelWidth: 130,
        store: store,
        queryMode: 'local',
        typeAhead: false,
        forceSelection: true,
        allowBlank : false
    });
                
    // a Combobox with a listener
    var simpleCombo = Ext.create('Ext.form.field.ComboBox', {
        fieldLabel: 'combo1',
        displayField: 'name',
        width: 320,
        labelWidth: 130,
        store: store,
        queryMode: 'local',
        typeAhead: false,
        forceSelection: true,
        allowBlank : false,
        listeners : { select : function()
                               { 
                                 simpleCombo2.setVisible(!simpleCombo2.isVisible());
                                 simpleCombo3.setVisible(!simpleCombo3.isVisible());
                                 simpleCombo4.setVisible(!simpleCombo4.isVisible());
                               }
                    }
    });

    Ext.create ('Ext.panel.Panel',
    {
      title : 'a panel',
      layout      : 'anchor',
      border      : true,
      autoScroll  : false,
      renderTo    : Ext.getBody(),
      items       : [{
                         items       : [
                         {
                           items        : [
                           {
                             items        : [
                             {
                               items        : [
                               {
                                 items        : [
                                 {
                                   items        : [
                                   {
                                     items        : [ simpleCombo,
                                                      simpleCombo2,
                                                      simpleCombo3,
                                                      simpleCombo4]
                                   }]
                                 }]
                               }]
                             }]
                           }]
                         }]
                      }]
            
    });
});

Edit : I confirm this pb is fixed in 4.0.2