I have  a Dell Latitude D600 with an ATI Mobility Radeon900 video.

I use it in a D-Port dock with an external monitor. I do not use the display on the laptop at work I only use the external monitor.  I then shut down take it home and plug it into the DPort dock at home but use the display on the laptop not an external monitor. The screen resolution does change when I do this which I understand because I am using a different display. I leave the setting alone and make no changes. What I can't figure out is when I bring it back to work I dock it with my external monitor plugged in and my screen resolution is not the same as it was the last time I docked here. The icons are moved around and resolution changed. I have to change it manually each time.

Any ideas on why the resolution does not stay the same when I bring it back to work?

Does it have something to do with one dock using an external monitor and the other dock using the laptop display?

Any help would be appreciated.