I wrote a greasemonkey script that removes them. See http://www.acooke.org/cute/HidingHNKa0.html

Hmmm. I wrote it for FireFox and haven't used it recently, after switching to Chrome, but it appears to install in Chrome too (oh; but the total top right is not removed - am looking into why now).

Note - it also "unhides" most greyed out comments.