title: The name 'ScriptManager' does not exist in the current context
body: <p>I copied some code to solve a problem with running JavaScript after an AJAX postback in ASP.Net. Unfortunately the new code gave me the following error when doing a build:</p>
  
  <pre><code>The name 'ScriptManager' does not exist in the current context
  </code></pre>
  
  <p>Now I've used the ScriptManager before, so why would it be giving me problems now? Isn't it available on all ASP.Net pages? I have a script manager on my master page after all...</p>