Yes and no.

Don't mistake Ajax with standard Javascript... It's a very crude misconception I've been reading around the web (and it's really begining bugging me, lol).

The drag/drop effect is just Javascript. Nothing to do with Ajax. You don't "need Ajax" for it.

Ajax comes in when saving your page settings. It's is nothing but the method used to send a small piece of information to the server. You modify the page locally with Javascript. The script sends a request to the Google server (Ajax), which the stores your settings.