Multiple ModalPopupExtenders are showing when calling Show for one

I have a form that has 3 modal popup extenders, each assigned to their own asp:panel, unique ok/cancel buttons...nothing programmitcally binds them except for them being on the same form.

I call the Modal.Show() method from the server, however, all 3 panels appear, no matter which popupextender invokes the Show(). I have done this before successfully. I believe the issue is that this is a content page that is within a UpdatePanel located on the MasterPage. This is the first time I have tried it this way. So basically the layout is:

Master Page
<UpdatePanel>
  <Content>
  </Content>
</UpdatePanel>

Has anyone encountered this before? I am using VS2010, .NET 4, C#.

I found the solution. I had all of them assing for the same TargetControlID, and once I gave each one a seperated TargetControlID, it worked. Before, I have used multiple MPE's with the same TargetControlID, and it has worked. They are normally basic buttons that I name "Worthless" and ha开发者_C百科ve their style set to display:none, since I normally call the Modal box on the server side by the Show() method. It did not work in this situation and needed a seperate TargetControlID for each MPE.