This also occurs when you get a Windows 7 dialog prompt - the background darkens, the prompt appears which you click to continue, it goes back into what you were doing, then 4 seconds later this greyish filter gets applied to everything again.
Admittedly it's only a small issue, as I can still use my laptop, but I've played with the colour settings for hours as I thought something was a bit "off" about the screen since the day I bought it and things appeared a little too washed out. I've messed around with the Windows built in brightness and gamma as well as my graphics card brightness/contrast/gamma/hue/saturation and although this helped optimise my screen, none of it seems to be related to this strange filter that seems to be getting applied to my screen. It's annoying because the screen looks great and vivid for the 4 seconds before this filter kicks in.
I've extensively searched Google, found a lot of questions and answers regarding the (obvious) power management settings and colour adjustment settings and this problem simply isn't related to either. I can't find a 5750G owners thread, or anything helpful released by Acer, so I was hoping one of the ever helpful EG forum members may have an inkling as to what may be causing this. Any ideas or advice would be great. Cheers.