[This is preliminary documentation and subject to change.]
Standard Dialog Manager (SDM) is an internal Microsoft code library that provides applications with a degree of independence from the differences between the Macintosh and Windows operating systems. SDM is primarily used for dialog boxes in the Microsoft Excel and Microsoft Word applications.
SDM presents problems for accessibility aids because it uses nonstandard implementations of dialog boxes. For example, SDM dialog box buttons don't use window handles in the usual sense. You cannot send messages to buttons and buttons aren't contained in the window list. The application using SDM communicates with it through a private interface.
The following illustration shows a sample dialog box from Microsoft Word. While it looks like a regular Windows dialog box using the pagetab control, it is really an SDM dialog box.