Hi,
same problem here, I am using latest extlib with Domino 8.5.3 CD3 (Dojo 1.5 included).
The listtextbox is inside a TabPane. When I change the settings of TabPane to "PartialRefresh" and "preventCache" , the failure does not come up in IE8, but the page is somehow frozen...no code works anymore...
No problems in Firefox.
Ingo