silverastrid 0 Newbie Poster

I have read online that the CalendarExtender doesn't trigger a postback when inside an UpdatePanel.
My page is similar to this:

        <UserControl />

Inside the UserControl is a textbox that has a CalendarExtender hooked to it. It causes a postback even to be triggered, so my if(IsPostBack) block is being hit when I don't want it to be. Can anyone tell me if this is because of the structure of the page? I haven't found much online to help. My textbox is not ReadOnly, either.