I'm using a Dell Inspiron laptop running Windows 7, with a Samsung SyncMaster P2250 connected via D-SUB as external display. The display seems to dynamically adjust it's brightness based on what's shown and I have found this to be quite frustrating: Darker scenes in movies get even darker, making it hard to distinguish anything. The display works fine if there are a lot of lit areas in what's currently shown.
How do I disable this feature? I've tried setting the brightness on the display, but it won't let me (brightness is gray, can't adjust it). The built-in screen of the laptop does not suffer from this issue.
Thanks in advance