Ho to avoid video Full Screen on desktop?

[bibo]

I have Matrox P750 setup with 2 monitors.
Everytime I open an application, like After Effects or Xpress DV, that has a video window in one of the 2 monitors, Matrox immediately maximises it in the 2nd monitor leaving me an option window to revert to desktop which I promptly do.
How can I avoid this inconvenience everytime I open a video application?
I know that what I am looking for is somewhere in Matrox PowerDesk, but I am a bit confused. Can anyone help me please.
Thanks in advance.

Bibo

[Kruzin]

In Powerdesk-HF, go to the 'Video Playback Settings', and clear the checkbox 'Use PureVideo/DVDMax'.