Vista - different screen resolution for each user? how to get rid of this?

Hello,
there seems to be a feature inside of vista... storing display resolution per user. This means that each user who uses the computer, can configure his display resolution separately and after the user logs in, the resolution will be set to his previous setting.
This may be nice for special usage, but is unwanted on my company network. The question is, why do this happens? I have not found any settings where this can be configured. All computers are domain members, but we dont know a policy which could cause this problem.
So my question: how can i configure that windows store the video settings per user or always for the complete system? My goal is that all user accounts on the computer should have the same resolution settings...