title: GridViewComboBoxColumn Telerik empty combobox until selected
body: <p>I have a telerik GridView with a GridViewComboBoxColumn - this control is empty until i click on an item in that column. Once I click on that column these values appear.</p>
  
  <pre><code>&lt;telerik:GridViewComboBoxColumn Header="Currency Quality" EditTriggers="CellClick" 
  ItemsSource="{Binding Path=CurrencyQualityList, Source={StaticResource mainPageViewModel}}" 
  SelectedValueMemberPath="DisplayText" 
  DataMemberBinding="{Binding CurrencyQuality, Mode=TwoWay}" DisplayMemberPath="DisplayText"&gt;
  &lt;/telerik:GridViewComboBoxColumn&gt;
  </code></pre>
  
  <p>I read that at the top of my page to put this in.</p>
  
  <pre><code>&lt;UserControl.Resources&gt;
      &lt;local:SearchRedemptionDetailViewModel x:Key="mainPageViewModel" /&gt;
  &lt;/UserControl.Resources&gt;
  </code></pre>
  
  <p>I am using an MVVM framework - I have an observable collection of type LookupValue in my ViewModel. The source for my combobox is CurrencyQualityList. My lookup value has two properties, DisplayText and Value - </p>
  
  <p>Even with these changes I still am unable to get the values to display. </p>