关于tab控件中添加子对话框的问题

各位大师，请问一下以下代码为嘛运行了不显示我加入的子对话框呢：
BOOL CXmManage::OnInitDialog()
{
    CDialog::OnInitDialog();
   
    // TODO: Add extra initialization here
    m_XmTab.InsertItem(0,"项目信息");
    m_XmTab.InsertItem(1,"取费费率");
    m_XmTab.InsertItem(2,"人工单价");
   
    m_XmTab.SetCurSel(0);
    CRect rect;
    m_XmTab.GetClientRect(rect);
    rect.DeflateRect(1,30,2,2);
   
    CDlgXmsx dlgxmsx;
    dlgxmsx.Create(IDD_DLGXMSX,&m_XmTab);
    dlgxmsx.MoveWindow(rect);
    dlgxmsx.ShowWindow(SW_SHOW);
   
    return TRUE;  // return TRUE unless you set the focus to a control
                  // EXCEPTION: OCX Property Pages should return FALSE
}