Comment 22 for bug 506018

@Martin: It turns out that having the mouseover region be the entire table cell is important. If we use something smaller (such as just the "8 days ago" link, or a patch band-aid icon), then the user can't move the mouse pointer down into the popup box to click on one of the links in there -- because as they move down into it, it disappears, because they've left the small region in which the popup is kept active.

So IMHO we should just keep the table cell as the active region. It takes a bit of getting used to, but it has the right behavior (more or less) once one is no longer surprised by it.