Why did Windows Aero disabled

In Windows Vista/7, Windows Aero can be temporarily disabled if certain software programs are used.

You will see this message at the bottom right corner of the screen:

It will change back to Windows Aero when the program is closed.

List of programs which can change into Windows Vista/7 Basic scheme

All full screen games/programs

Macromedia Flash Basic 8 (Not affected in Windows Vista)

Macromedia Flash Professional 8 (Not affected Windows Vista)

VisualBoyAdvance (When the bottom left status message caption with the red text appears such as "Wrote state 1")

DeSmuME NINTENDO DS Emulator (When DirectDraw SW mode is set)

Ulead DVD Player (When playing a video/disc)

If you think there are some other programs not listed above, please e-mail to megah961107@hotmail.com so I can add some more.