title: httpcontext.current.handler.master returns null after sometime
body: <p>I am facing a problem in ASP.NET. I have a dropdownlist in Master Page and I am accessing it in a library outside the UI project using the below code : </p>
  
  <pre><code> Page page = HttpContext.Current.Handler as Page;
  
   if (page != null)
   {
       return page.Master.FindControl("MyDdl") as DropDownList;
   }
  </code></pre>
  
  <p>This code works fine normally. But sometimes if I remain inactive for 15 to 20 minutes and then cause a postback (e.g. Click button, change menu etc..) Master property of the page becomes null. i.e. <code>page.Master</code> starts returning null. Then I press F5 to refresh the page and it starts working again. I also searched google but did not find any relative answer. Can anyone guide me what is going on here?</p>