title: WPF ComboBox resets selected item when item-source changes
body: <p>Consider the following XAML:</p>
  
  <pre><code>&lt;ComboBox Name="CompanyComboBox" 
      HorizontalAlignment="Stretch"
      ItemsSource="{Binding Path=GlobalData.Companies}" 
      SelectedValuePath="Id"
      SelectedValue="{Binding Customer.CompanyId, ValidatesOnDataErrors=True}"
      DisplayMemberPath="Name" /&gt;
  </code></pre>
  
  <p><code>GlobalData.Companies</code> is a collection (<code>IEnumerable&lt;Company&gt;</code>) of companies; this collection can be reloaded on background (it is downloaded from a webservice). When this happens, ComboBox correctly reloads items via binding. However as a side-effect, it also resets the selected item!</p>
  
  <p>I have used Reflector to inspect combo-box sources and apparently this is intended behavior.</p>
  
  <p>Is there any "nice" way how to get around this? What I want to achieve, is that if the user selects "Company A" and reloads list of companies afterwards, then "Company A" stays selected (assuming it is in the new list).</p>