Ray (from the very first comment): the images change names at the point I switch from opaque-corner images to transparent images. In other words, “norm_right.gif” is the opaque version, “right.gif” is the new transparent version. All (8) images are available in the same directory.
The “flashing” in IE/Win browsers is most likely due to the fact that you’ve turned off caching in preferences. Even without “a:hover” rules, IE has trouble holding a background image steady on anchors if you’ve specified “Every visit to the page” for temporary files.
The latest versions of Safari, Mozilla, and Firebird *should not* have any problems with rendering any of these examples, according to all the browsers we’ve seen.
I intentionally don’t cover any philosophical or usability issues related to the use of tabs, so that the article stays focused on a technique for an already widely popular interface metaphor. Whether tabs are appropriate for any site is up to the team or individual responsible for that site.
There are a few variations of the technique I didn’t cover, for the sake of keeping the article as short as possible. Like using a unique ID for each list item, then another on the body element to pinpoint the current tab, instead of moving around id=“current” from one list item to another. More complex image-changing rollovers would be possible with the same markup by using li:hover and a:hover to affect the background images too. But be wary of the fact that IE/Win currently does not support the :hover pseudo-class on any element other than an anchor.
Thanks for the feedback so far. Keep it coming.