Darker display during playing movie (1 Viewer)

[josetto]

MediaPortal Version: 1.1.3.0
MediaPortal Skin: Blue3wide
Windows Version: Windows 7
CPU Type: Inte Core2 Duo T7250
HDD: Fujitsu KHY2250BH 250 GB
Memory: 3 GB
Motherboard:
Video Card: GeForce 8400M GS
Video Card Driver: 8.17.12.6099
Sound Card: Realteck HD Audio
Sound Card AC3:
Sound Card Driver: 6.0.1.6101
1. TV Card:
1. TV Card Type:
1. TV Card Driver:
2. TV Card:
2. TV Card Type:
2. TV Card Driver:
3. TV Card:
3. TV Card Type:
3. TV Card Driver:
4. TV Card:
4. TV Card Type:
4. TV Card Driver:
MPEG2 Video Codec:
MPEG2 Audio Codec:
h.264 Video Codec:
Satelite/CableTV Provider:
HTPC Case:
Cooling:
Power Supply:
Remote:
TV:
TV - HTPC Connection:

Hi, I have a problem, during playing a movie after about 5 minutes the display goes darker. It looks like MP don't ignore my power settings in screensaver, where I set to darker display after 5 minutes and so it seems OS is idle during playing movie (I never met with this before on other movie player). Is it a bug or is it possible to set it somewhere? THX