title: Update Panel working very slow
body: <p>I'm writing an app in which user can register. While registering the one may choose several options and according to these regiester fields are visible or not and are required or not. 
  I came up with an idea that all fields will be in in the updatePanel and when users changes registration options I would set visibility of these fields on the server side. </p>
  
  <p>It works but incredibly slow and whats more on the FF I have the given error:</p>
  
  <blockquote>
    <p>The state information is invalid for
    this page and might be corrupted</p>
  </blockquote>
  
  <p>3 checkboxes with other fields are in the updatePanel</p>
  
  <p>Each field is in dl tag with <code>runat="server&gt;</code></p>
  
  <p>I had to do it like that cause for "required" option I simply add css class to this dl (need in in javascript validation. If field should be visible I set visible="false" for given dl and then that field for example FirstName with title and so on isn visible after postback.</p>
  
  <p>Am I doing something wrong ? Why does it take so long (~4 min on localhost) and in firefox it doesnt really work (when I use debug I think that process completes without errors on ff, I dont understand that at all :)</p>
  
  <p>If update Panel is so weak what would be other option to change visibility and adding required class to all dls. Logic is quite complicated and has to make query to DB so simple javascript would be quite tricky.</p>
  
  <p>Thanks for any hints,</p>
  
  <p>Oh and I'm using ASP.Net and cant upgrade on this project.</p>
  
  <p>Thanks for help,
  bye</p>