Track Ir in Cliffs of Dover

[airsheep]

hi,
another question regarding to trackir/gunsight wiew:
when I start a quick mission I see the crosshair in the middle of the revi, looks like this:

afer a few minutes the crosshair is "sliding down" and I can see only the upper half of it, just like in this picture (tr center button doesn't help):

I have tried many things to fix it but nothing helped, I have a trackir 4pro, and I only use the x, y axes instead of all 6 axes. Does anybody else have the same problem?