Switching monitors (Fn+F8) causes constant CTRL++ input on laptop

I've hooked up my Inspiron 9400 to a Samsung 40" LCD HD TV with a VGA cable. It shows up as the second monitor and seems to drive it okay. The problem is that when I try to switch to it using Fn+F8 it looks okay until I try to open and use a window. The first time I hit Fn+F8 it adds the Sammie as an extended monitor. When I open Explorer and click anywhere in the window, the view immedialtely starts to zoom in until it reaches it's limit as if I was holding down CTRL++. In Firefox it increases the text size instead of zooming, again as if I was holding down CTRL++. In Word it does the same as Explorer. The only way to recover is to log off and back on which allows it to work normally regardless of the configuration.

If I use the Properties window to add the Sammie as an extended second monitor it works flawlessly. While it's in that mode if I try to switch to the Sammie using Fn+F8 it goes back to having the problem.

So it seems that only when I use Fn+F8 to switch does it cause this problem.

Any attempt to return the window to normal results in it going to normal and immediately zooming again as if holding CTRL++. No combination of keystrokes seems to affect it.

I'm running Windows XP MCE w/ SP2, I've cleaned the registry, installed the latest drivers, installed all the latest updates and patches and nothing seems to help.

Anyone have any ideas?

Steve