Using Safari Version 2.0.4 (419.3). First page on /index on slashdot, first story. click tag. type in tag. autocomplete starts to fire off, but the box itself is *way* at the top of the page.
infact, I saw this happen to a site I was updating to _134 yesterday which the old base.css (or maybe site.css representing slashcode.css) was cached so the css my browser was using lacked the #ac-select's. Oddly enough w/o that CSS in there, that autocomplete text box positioning is *exactly* where I'm seeing it now on Slashdot.
i'll attach a screencap.
screenshot png