title: Designer cannot be shown for this file because none of the classes within it can be designd
body: <p>First off, I am aware there are an abundance of questions on this specific error on SO, however none of their solutions are particularly feasible for me (such as ensuring the use of a particular .NET version)</p>
  
  <p>I have a few classes, which do not throw a warning. Here's one of them (they're all just empty shells at the moment)</p>
  
  <pre><code>using Infrastructure.Common.Controls;
  
  namespace WorkSpace.Accounts
  {
      public interface ICtlAccountsContacts
      {}
  
      public partial class CtlAccountsContacts : BoundControl, ICtlAccountsContacts
      {
          public CtlAccountsContacts()
          {
              InitializeComponent();
          }
      }
  }
  </code></pre>
  
  <p>This class however, does throw the warning in the title.</p>
  
  <pre><code>using Infrastructure.Common.Controls;
  
  namespace WorkSpace.Accounts
  {
      public interface ICtlAccountsInternational
      {}
  
      public partial class CtlAccountsInternational : BoundControl, ICtlAccountsInternational
      {
          public CtlAccountsInternational()
          {
              InitializeComponent();
          }
      }
  }
  </code></pre>
  
  <p><code>BoundControl</code> is a custom class that inherits from DevExpress' <code>XtraUserControl</code>, which inherits from <code>System.Windows.Forms.UserControl</code> so I don't see why I should be able to view one control in Design view and not the other.</p>
  
  <p>They're part of the same project, and like I said same namespace. I've tried all sorts of combinations of Build, Rebuild, rebooting... Everything I can think of. Still get that warning.</p>