The links in the above URL (it happens on any page that uses the stylesheet http://www.fas.harvard.edu/~dbaron/style/index - note that this is browser- sniffed so don't pull it using NN 4.x) don't act like links in any way once all the stylesheets are loaded. (I get hovers from forest.css while they are loading, along with other normal behavior.) There are no hover changes, mouse changes, and clicking on them doesn't do anything. I'm using build 99-04-20 (which is dated 99-04-21). It didn't happen in build 99-04-14. There weren't any windows builds on mozilla.org in the interim.
Actually, this broke between 99-04-12 and 99-04-14.
Looks like event handling is broken for floated boxes. Links outside the two column floated boxes work fine.
Another, probably related event handling problem is in http://www.fas.harvard.edu/~dbaron/tests/nglayout/linkborder (epecially if you size the page so that the image does not start a line, since that makes the area bigger): Clicking on the big blank areas to the left and right of the image acts as though it is clicking on the link in the image and activates the link. Bug 5407 is related.
5407 is strictly a repaint issue in style code, not related.
In http://www.fas.harvard.edu/~dbaron/css/fonts/aspect you can click practically anwhere in the vertical margins of boxes to activate the image link near the bottom. This bug is disturbing and makes it difficult to use the browser. Raising priority from default P3 up to P2.
All the problems described in this bug seem fixed in today's build.
Cool. Well that means this was likely s side of effect of some missed changes when I did a checkin a couple weeks ago. The partial changes in that checkin must have broken this behavior. The rest of the fixes went in last week. Closing this since it seems to be okay.