Set focus on Extjs textfield

Question

Currently I got problem with setting focus on extjs textfield. When form show, I want to set focus to First name text box and I try to use build in function focus() but stil

Answer 1

UIManager.SetFocusTo = function (row, column) {
    var grd = Ext.getCmp('gridgrn');
    grd.editingPlugin.startEditByPosition({ 'column': column, 'row': row });

}