title: 'The page has controls that require a Master Page reference, but none is specified' issue
body: <p>I'm getting this output:<img src="https://i.stack.imgur.com/7pzKW.png" alt="enter image description here"></p>
  
  <p>even though my page contains <code>MasterPageFile="~/Site1.Master"</code></p>
  
  <p>Here's my page's source code:</p>
  
  <pre><code>&lt;%@ Language="C#" MasterPageFile="~/Site1.Master" AutoEventWireup="true" CodeBehind="WebForm2.aspx.cs" Inherits="Projekt.NET.WebForm2" %&gt;
  
  &lt;asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server"&gt;
  &lt;title&gt;gowno&lt;/title&gt;
  &lt;/asp:Content&gt;
  
  &lt;asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server"&gt;
  hahahahahahaa
  &lt;/asp:Content&gt;
  </code></pre>