Ajax UpdatePanelAnimationExtender only works on first use

I have an asp.net ajax updatePanelAnimationExtender that is used to fade a save confirmation message, which looks like this:

<ajaxToolkit:UpdatePanelAnimationExtender ID="UpdatePanelAnimationExtender2" runat="server" TargetControlID="uppExp">
            <Animations>
                <OnUpdated>
                    <Sequence>
                     <Parallel duration=".5">
                                <HideAction AnimationTarget="pnlSuccess" Visible="开发者_JAVA百科True" />
                            </Parallel>
                            <Parallel duration=".25" Fps="30"> 
                                 <FadeOut AnimationTarget="pnlSuccess"  />            
                            </Parallel> 
                    </Sequence>
                </OnUpdated>
            </Animations>
</ajaxToolkit:UpdatePanelAnimationExtender> 

It works great the first time it runs, but after that, on subsequent saves it does not run. This only happens in Internet Explorer (7 and 8) it works fine in Firefox and Chrome. Any ideas on how to get this to work properly in IE?

You probably haven't included the code (animation extender) in update panel, so it's not working second time...