It does, this one in fact: dojo.registerModulePath('extlib', '/xsp/.ibmxspres/.extlib');
I have been able to narrow it down a bit since my post, it seems to only happen on our iSeries (i5OSv4). Other controls work , for instance this particular form is using a tab container and content panes, they work fine. Also, yesterday I discovered another issue (on the iSeries), with a select control. It works, only the ok button won't hide the dialog. So you can select something, hit ok and it will populate the bound field, but then you have to hit cancel or x out of the dialog to close it.
I've noticed other oddities between platforms with Xpages, and I'm thinking this might just be a product of a bigger problem with Domino. I use Windows 2003 32-bit running on a VPC for dev, we have a 2003 32-bit and 64-bit production box as well as the iSeries, one of the three will almost always render something weird (and not always the iSeries) that looks perfectly fine on the other servers (usually minor layout issues but irritating nonetheless). I would expect Domino to produce the same source regardless of the server platform it's running on, assuming the Domino versions are the same across all platforms, but this doesn't seem to be the case.