Microsoft Windows Architecture for Developers Training Kit
Add OLE Drag and Drop Functionality
Users who are comfortable with the Windows interface will want to use the same techniques to create, drag, and activate objects in your application. OLE drag-and-drop allows a user to move data around the desktop, within Windows Explorer, and to or from other applications that support the protocol.
Drag-and-drop functionality also makes your application more consistent with the Windows interface and with other applications that adopt OLE functionality. As a result, users will learn how to use your software more easily, and your application will work more seamlessly with other applications that provide OLE support.