UpdatePanelAnimationExtender - OnUpdating Will Always Play
Did you know that the when a partial postback starts, the OnUpdating animation for all of the UpdatePanelAnimationExtender's on the page will play. Here is part of the documentation taken from the UpdatePanelAnimationExtender page It is important to note that because of the UpdatePanel architecture, the OnUpdating animation will always play when any partial postback starts, but the OnUpdated animation will only play at the end of a partial postback if its UpdatePanel was changed (note: setting the UpdatePanel's UpdateMode="Always" will ensure the OnUpdated animation plays when every partial postback completes). Unless I am mistaken, I believe this behavior is for the scenario where an UpdatePanel's UpdateMode is set to Conditional, and the code on the server handling the partial postback explicitly calls Update on the UpdatePanel. In this case, where logic on the server decides if an UpdatePanel is refreshed, the UpdatePanelAnimationExtender has no way of knowing if it should have played the...