private void PrepareCollection(StyleOptionCollection opsCollection)
 {
     if (opsCollection != null)
     {
         PrimaryStyleCollection            = opsCollection;
         OptionsCollection                 = opsCollection.Clone();
         OptionsCollection.ValidateHandler = expression => NewExpressionString.EqIgnoreCase(expression) ? StringResources.StyleOptionConditionNotDefined : null;
     }
 }
 private bool IsNewExpressionString()
 {
     return(IsSelectedItem() && SelectedItem.ExpressionString != null &&
            NewExpressionString.EqIgnoreCase(SelectedItem.ExpressionString));
 }