Window title icon in CXTPTaskDialog

Hi Folks,
I'm facing a really strange problem. I construct a TaskDlg the following way:

CXTPTaskDialog taskDlg;
taskDlg.SetUseComCtl32(TRUE);
//  taskDlg.SetCommonButtons(TDCBF_CANCEL_BUTTON);
//  taskDlg.EnableCancellation();
taskDlg.SetWindowTitle(_T("Update"));
taskDlg.SetMainInstruction(_T("lalala"));
taskDlg.SetContent(_T("Page 1"));
taskDlg.SetMainIcon(MAKEINTRESOURCE(IDI_DOWNLOAD));
taskDlg.AddButton(_T("Start"), ID_BUTTON_NEXT);
taskDlg.DoModal();

Really nothing fancy.
Now, if I add a button with the ID IDCANCEL or if I uncomment one of the both lines above and I get a Cancel Button (okay), a red Dlg close box and an icon in the window title. Why that, why the icon?
I investigated the sample, but I never see an icon in the window title.

Whats wrong with my task dlg? How can I avoid the window title icon? I only want the main icon - not two same icons.

If I set SetUseComCtl32 to false, the window title icon disapears.
Any hints appreciated! (running on Win7 with MfC 13.4.2)


And the SetMainIcon() seems not to work in OnDialogConstructed. The main icon remains unset.
In CJ Timer sample app, setting the icon via the same method is no problem, but something must be different here...