A FormVIew Question!

Hi Everyone:

When I show a CFormView in a CXTSplitterWnd's pane,the  edit and comobx that I derived from CXTFlatEdit and CXTFlatComboBox,the flat appearance works well,but it doesn't work when I put a FormView into a CXTTabView,even  XTFlatEdit and XTFlatComboBox. And many pretty buttons including ButtonST,the classic button, can't work too!Whether i have lose some declaration?Here are code:

 class CSalesCustMainView : public CFormView
{
CXTFlatEdit           m_FaxXT;    

...................

}

void CSalesCustMainView::DoDataExchange(CDataExchange* pDX)
{
 CFormView::DoDataExchange(pDX);
 DDX_Text(pDX, IDC_FAX_EDIT, m_FaxEdit);
............................

}