Fullscreen trouble with matrox triplehead 2 go

hi patchers…
I am having some troubles with a matrox triplehead2go here.
the problem is:
Going full screen does not what it should do. I am using a well-supported 3840x1024 resolution on 60hz. I have only one monitor activated in the display properties. The correct resolution is stored within the patch, even after restarting.
BUT: Most of the time going fullscreen (per pin) the renderer would squeeze the complete image in the left of the three outputs of the triplehead. sometimes it works, but most of the time not.I’ve even tried the /dda commandline switch, but without success.
Did anyone experience something like this? There must be an easy trick or something as it workes occasionally.

I tried to add a second monitor in the display properties, which resulted in working better, but still: the renderer now drops the resolution and sets it back to 1024x768.
Is there a way to force in the resolution?


aha, finally:
Physically changing the outputs of the grafics card did the job. Same setting, only switched cables and devices in the display properties.
Isn’t that strange?