Datapicker in sencha ExpJs. How to change the date when you click on the arrows to the right and the lion

items: [{ xtype: 'button', cls: 'contactBtn', scale: 'large', text: '+', handler: 'onAddClick', }, { xtype: 'button', align: 'left', text: '<', scale: 'large', }, { xtype: 'button', name: 'someDate', type: 'String', columnWidth: 0.9, scale: 'large', text: Ext.Date.format(new Date(), 'md-Y'), listeners: { change: 'onDateChanged' } }, { xtype: 'button', text: '>', scale: 'large', }, { title: 'Sum: ', columnWidth: 0.1, } ],