MS states, with regard to the Application Manifest compatibility section:
Manifestation of Change
Applications without a Compatibility section in their manifest will receive Windows Vista behavior by default on Windows 7 and future Windows versions. (...)
(...)
DirectDraw Lock
- Windows 7: Applications manifested for Windows 7 cannot (...)
- Windows Vista (default): Applications will be able to (...) Running the application turns off Desktop Window Manager.
The note is repeated for the next DirectDraw entry.
What the heck does this signify? None of or desktop (MFC) apps defines a compatibility manifest, but we've never noticed anything on "turning off" on any Desktop.