Rick,
The MSDN library tells the following :
Windows 95/98/Me: The system can support a maximum of 255 controls per dialog box template. To place more than 255 controls in a dialog box, create the controls in the WM_INITDIALOG message handler rather than placing them in the template.
So it is not a C++ limit, but a dialog-box template limit which should not be there under NT/2000/XP. Marcel