Not sure if this was a bug or if I might have missed a point in the setup.

MacPro QuadCore 3GHz / X1900 - output 1 - 1024x768 (Mix 1) , output 2 - TripleHead2Go with 3 x 1024x768 (Mix 2 thru 4).
Seamless projection over 4 outputs.
All mixes were set to keystone mode.

Mix 2 had a reduced brightness compared to all other mixes. It missed like two steps in the grey-step setup-picture.

All mixes were set to keystone mode.
I know I have a gamma correction for each screen - but nor for each mix. There was nothing I could do to get Mix 2 to the same brightness as the others.
My final solution was to copy all settings from Mix 2 to Mix 5 and then it worked perfectly.

Is it possible that there is a mix gamma setup somewhere in the XML-setup file that might have been on a wrong value? - I was a rental Catalyst system.

I also had problems with the output of the TH2G when playing some certain files: from time to time I had horizontal lines on the center output of the TH2G and sometimes the whole output dropped out.
I was not a problem of cabling to the projectors as we had the same effect
when plugging another projector in the center output of the TH2G.
With other files everything worked fine...

Cheers,

Olli