Invalid Postback occurring?
<p>I keep getting this error:</p>

<blockquote>
  <p>Invalid postback or callback argument.  Event validation is enabled
  using  in configuration or &lt;%@
  Page EnableEventValidation="true" %> in a page.  For security
  purposes, this feature verifies that arguments to postback or callback
  events originate from the server control that originally rendered
  them.  If the data is valid and expected, use the
  ClientScriptManager.RegisterForEventValidation method in order to
  register the postback or callback data for validation.</p>
</blockquote>

<p>I have registered the ClientScriptMagner.Regis.... but still nothing.</p>

<p>I have dropdownlist's in a control and when my form is submitted, this happens.</p>

<p>How do I fix this?</p>
