Has anybody added extra RAM to their PC after installing Vista?

I added an extra 2GB of RAM, to bring the total up to 4GB earlier today, and I was very surprised to find that after waking it up again this evening it was telling me it had deactivated because of hardware changes I was able to reactivate over the Internet with no problem, so it's not that big a deal, but I'm sure it isn't supposed to require reactivation after a simple RAM addition. If this has happened to anyone else then I'll report it as a bug, if not, then I'll just put it down to an odd glitch.