I am trying to set the default value in the select box, it sets the value in the select box, but when I click the select box I got the first value checked,
May some body have any solution to the problem;

Code:
Ext.getCmp('user_list').add({
		style: 'margin:5px;',
		xtype: 'selectfield',
		label: 'List',
		name: 'myList',
		id: 'myList',
		store: listStore,
		value: datavalues[default_list_id_todisplay].list_name,
		displayField: 'list_name',
		valueField: 'list_id',
		listeners: {
		afterrender: function(){


			Ext.getCmp('myList').value = datavalues[default_list_id_todisplay].list_id;
			comboDefaultValue = datavalues[default_list_id_todisplay].list_name;
		}
	}
	});
	
	Ext.getCmp('user_list').doComponentLayout();
	Ext.getCmp('codePanel').doLayout();
	}