title: UserControl cannot be displayed in Designer - null object reference
body: <p>I have a created a UserControl with a combobox in it. This combobox is populated from a xml, when this is not present, it is loaded from resource file.<br>
  It works fine in the program, but it can't be displayed in designer - it says: "Object reference not set to an instance of an object."</p>
  
  <p>In the class responsible for loading the list from xml the null reference check is skipped for reasons beyond my understanding...</p>
  
  <pre><code>public SortedDictionary&lt;string, string&gt; Countries
  {
      get
      {
          if (object.ReferenceEquals(countries, null))
          {
              GetCountryList();
          }
          return countries;
      }
  }
  </code></pre>
  
  <p>Populating of the comboBox goes like this:</p>
  
  <pre><code>comboBoxCountry.DataSource = new BindingSource(Program.language.Countries, null);
  </code></pre>
  
  <p><code>Program.language</code> is initialized in Program, but it does not help for the Designer.  </p>
  
  <p>The question is, how (when, at what event) should I populate the ComboBox (=load list from xml) to be able to display my control in designer.</p>