Ajax (sigh) Pet Peeve

I've finally given up and added 'ajax' to my vocabulary as a synonym for "JS remoting".  But I've got a bone to pick with people building ajax apps: neat UI trickery has to leave the UI in a consistent state or you're making the UI worse instead of better.
The particular example that is continually annoying [...]

DHTML ComboBox Widget

With the wife and kid out of town, I didn't have much to do, so I spent the afternoon building a simple DHTML combobox widget. Yes, I'm that much of a geek. I haven't done a lot of testing, but I built it exclusively in FireFox, aiming for compatibility, and IE6 behaved exactly [...]