Well... iframes simplify the extension, but mess up our access to the document.
We now break the iframe encapsulation to download the page... annoyingly enough even with the chrom extension it is difficult to just break the iframe entirely (redirecting the url so it looks like it is the same page is probably the best option).
Dispose should not work... also remoted Set in the map, and simplified a lot of the sync logic (it is probably broken now).