It looks good in Window mode, but when I switch to Fullscreen, the texture seems brighter or lighter. For example, I have a sky dome. I set the emissive to full 1.0. It appears normal in Window, but in Fullscreen it''s plain white with tiny little bluish here and there. Any reason why?

possibly due to gamma changes the drivers may do when switching to fullscreen using dx. check your video card config.