Çetin-

>OutputCache in user control didn't work? :(

From the help it seems it's the same as setting the HttpCachePolicy, which I do use, but it's not related to this problem, AFAICT. It's not really a caching issue. BTW, changing to instantiating my class (with the DataReader) on PostBacks as well as initial load is working fine.

>BTW why are you putting the control in a session var? Wouldn't adding dataset to Cache be better?

Hm...I'm probably missing why you're suggesting the cache instead of a session variable. IAC, I am saving the DataReader to a sesssion variable. Saving the dropdown to a session var was a bit of a desperate try.