lib/Ext/MessageBox.js
function(newButtons) {
        var me = this;

        // If there are no new buttons or it is an empty array, set newButtons
        // to false
        newButtons = (!newButtons || newButtons.length === 0) ? false : newButtons;

        if (newButtons) {
            if (me.buttonsToolbar) {
                me.buttonsToolbar.show();
                me.buttonsToolbar.removeAll();
                me.buttonsToolbar.setItems(newButtons);
            } else {
                var layout = {
                    type: 'hbox',
                    pack: 'center'
                };

                var isFlexed = Ext.theme.is.CupertinoClassic  || Ext.theme.is.MountainView  || Ext.theme.is.Blackberry || Ext.theme.is.Blackberry103;

                me.buttonsToolbar = Ext.create('Ext.Toolbar', {
                    docked: 'bottom',
                    defaultType: 'button',
                    defaults: {
                        flex: (isFlexed) ? 1 : undefined,
                        ui: (Ext.theme.is.Blackberry || Ext.theme.is.Blackberry103) ? 'action' : undefined
                    },
                    layout: layout,
                    ui: me.getUi(),
                    cls: me.getBaseCls() + '-buttons',
                    items: newButtons
                });

                me.add(me.buttonsToolbar);
            }
        } else if (me.buttonsToolbar) {
            me.buttonsToolbar.hide();
        }
    }
function(newButtons) {
        var me = this;

        // If there are no new buttons or it is an empty array, set newButtons
        // to false
        newButtons = (!newButtons || newButtons.length === 0) ? false : newButtons;

        if (newButtons) {
            if (me.buttonsToolbar) {
                me.buttonsToolbar.show();
                me.buttonsToolbar.removeAll();
                me.buttonsToolbar.setItems(newButtons);
            } else {
                var layout = {
                    type: 'hbox',
                    pack: 'center'
                };

                var isFlexed = Ext.theme.is.CupertinoClassic  || Ext.theme.is.MountainView  || Ext.theme.is.Blackberry || Ext.theme.is.Blackberry103;

                me.buttonsToolbar = Ext.create('Ext.Toolbar', {
                    docked: 'bottom',
                    defaultType: 'button',
                    defaults: {
                        flex: (isFlexed) ? 1 : undefined,
                        ui: (Ext.theme.is.Blackberry || Ext.theme.is.Blackberry103) ? 'action' : undefined
                    },
                    layout: layout,
                    ui: me.getUi(),
                    cls: me.getBaseCls() + '-buttons',
                    items: newButtons
                });

                me.add(me.buttonsToolbar);
            }
        } else if (me.buttonsToolbar) {
            me.buttonsToolbar.hide();
        }
    }
Adds the new {@link Ext.Toolbar} instance into this container.
@private