c# - Weird UpdatePanel Issue -

I have a page that has an updated panel that wraps an AJAX tabord with 4 tabs. Each tab has its user control tab, one of the tabs is another update panel (an ASINC is used to trigger a postback, when a particular dropdown list is selected to remove the selected indexed event). In this tab, I have a number of controls, where there is a label, then wrapping a panel which requires the field ("see the HTML given below for the sample") to provide a "*":

  & lt; ASP: Labels ID = "LLL-verified language" run = "server" text = "preferred language:" & gt; & Lt; Asp: panel id = "pnlPrefLangReq" runat = "server" CssClass = "fieldSetRequired" & gt; & Lt; Period & gt; * & Lt; / Span & gt; & Lt; / ASP: Cell & gt; & Lt; / ASP: Labels & gt;  

It's all right and useless when the user leaves when a required field is submitted without filling it. The site correctly displays the error message to the user, but when you look at this tab, it is actually re-submitted with "*" for the second time, so I think something looks like this:

  Preferred language: * * [dropdown control]  

I do not understand why this is the second time in the example why the device has been provided Try to capture Ntrn is to render and tried to put breakpoints on init methods, but they never left (I think because there is no real postback, as is happening in all of its updates panel). I'm at a loss. Anyone have any ideas?