AE CC loses connection with second monitor and audio mixer (BLACKMAGIC) when switching to desktop

specifications:
Mac OsX 10.7.5

AE cc (part of creative cloud, up-to-date) NOT TRIAL VERSION

software for connecting monitor and adui mix panel: Blackmagic Desktop Video 10.0
second monitor: Sony Trimaster EL PVM 2541

audio mix panel: Behringer Xenyx x1204USB audio mixer

Blackmagic connects the Sony screen + Behringer Xenyx x1204USB audio mixer to the mac computer.

the problem:
When working in after effects, we link the program to show the video preview on the second screen (the sony one)

While the work area is still visible on the Mac screen.

The audio is also regulated through Blackmagic so we can mix on the xenyx mix panel.

Everything works fine as long as we stay in after effects.

If, for a brief moment, even a second, we swhitch to the desktop, or an other program (internet, acrobat reader, etc) After effects looses the connection to Blackmagic (forgets it exists). So we suddenly have no audio, or no longer a seperate video preview image.

The option to select Blackmagic in the dropdown menu is also gone.

If we restart After effects though, it's connected again.

Any ideas?

I added two screenshots to clarify.
The screenshots is when it does work, and after effects still recognizes blackmagic.

Cheers,
Andreas