title: Error on Display Estimated Execution Plan with window function
body: <p>I just wanted to have a look how the execution plan of a query changes, when i add window functions like LAG().</p>
  
  <p>But, when i add a window function to my query like LAG() &amp; click on "Display Estimated Execution Plan" it returns me following error.</p>
  
  <pre><code>An error occurred while executing batch. Error message is: Error processing execution plan results. The error message is:
  There is an error in XML document (1, 12308).
  Instance validation error: 'Window Spool' is not a valid value for PhysicalOpType.
  </code></pre>
  
  <p>SQL Server: </p>
  
  <pre><code>Microsoft SQL Server 2016 (SP1) (KB3182545) 
  13.0.4001.0 (X64)   Oct 28 2016 18:17:30   
  Copyright (c) Microsoft Corporation  Enterprise Edition (64-bit) 
  on Windows Server 2012 R2 Standard 6.3 &lt;X64&gt; (Build 9600: ) (Hypervisor)
  </code></pre>
  
  <p>I never experienced this behavior before. Any ideas why the execution plan can't be estimated?</p>