I had exactly this same problem, and again only on IE8.
This was using RichFaces 3.3.3 and JBOSS AS 5.1.
Never managed to track it down though - so sorry can't help you.
I am now in the process of migration to JBOSS AS 6 (Not 7 yet!) and Richfaces 4 with JSF 2 and it has not happenned again (yet).
I'll post back here if it happens again.
Thanks for replying Rich. I'm just glad I'm not the only person who's had this problem.
I'm going to attempt to upgrade Richfaces or upgrade Prototype. If I learn anything else. I'll post it here.
The only solution I could find was to build Richfaces from scratch with an upgraded Prototype library.
We have the same issue. Sometimes, the page doesn't finish loading (some error JS are thrown, first one from prototype ; CSS are not loaded).
Could you please describe which version of prototype do you finaly use ?
Do you have side effects using an updated prototype ?
Sorry for not replying sooner.
I upgraded to prototype 1.7. We're not using many components, but tab, tabPanel, dataTable, calendar, modalPanel, and simpleTogglePanel all worked without problems.