Throttle Conflict

Not a big deal but curious. I have a lot going on with the Saitek Pro Yoke, Peddles. separate Throttle Quadrant and X52 Pro. I have all the buttons going through FSUIPC except the Hat Switch and the X52 Axis going through the FSUIPC as well. The issue is when first running the program take the default cessna full throttle going down the runway and the open up a window say the GPS it kills the throttle. Only the first time then everything works fine. I know, just open a window up before hitting the throttle fixes it but wondered what causes the conflict. The Pro Yoke and Pro Yoke throttle quadrant goes through the FSX default controls avoiding other throttle conflicts. So, any ideas?