Can't use EditItem method of CXTEditListBox class

I am using CXTEditListBox to edit a list of items. There is a need to prevent duplicate entry in the list. So I maped the ON_LBN_XT_LABELEDITEND message. Inside the message handle function, I check the text of current edit item. If the same item already exist. I try to force the user to edit the current item again. I use void CXTEditListBox.EditItem(int iItem) to edit the item.  However, the item selected doesn't entry a edit state.  I tried to put EnableEdit() in front of it . Still not working. Does anyone know how to solve this problem?

Thanks,


ON_LBN_XT_LABELEDITEND(IDC_LIST_FRAMEWORK, OnLabelEditEnd)

void CMyDlg::OnLabelEditEnd()
{
    int nSel = m_lstFramework.GetCurrentIndex();
    if( nSel == LB_ERR ) return;
    CString strText; 
    m_lstFramework.GetText(nSel, strText);
    strText.Trim();
    if( IsNameDuplicated(strText, nSel) )
    {
          //show a message.
          ...
          //this doesn't work.
          m_lstFramework.EditItem(nSel);
    }
}