I am using SL5 and Test Studio. I Built a small SL app with some labels and a RadMaskedTextBox. (See xaml below.) <Grid x:Name="LayoutRoot" HorizontalAlignment="Center" Height="115" Width="185"> <StackPanel Orientation="Vertical"> <Border Style="{StaticResource GridCellDataStyle}"> <sdk:Label Name="FirstName" Content="John" HorizontalAlignment="Stretch" FontSize="15" /> </Border> <Border Style="{StaticResource GridCellDataStyle}"> <sdk:Label Name="LastName" Content="Doe" HorizontalAlignment="Stretch" FontSize="15" /> </Border> <Border Style="{StaticResource GridCellDataStyle}"> <sdk:Label Content="{Binding Path=UserName}" HorizontalAlignment="Stretch" FontSize="15" /> </Border> <Border Grid.Row="1" Grid.Column="2" Style="{StaticResource GridCellDataStyle}"> <telerik:RadMaskedTextBox MaskType="None" Width="140" Value="{Binding CurrentQuantity, Mode=TwoWay}" IsReadOnly="True" IsEnabled="False" MaxLength="50" /> </Border> </StackPanel> </Grid> I created a test in Test Studio and began recording. However, I cannot build a verification on the RadMaskedTextBox. The verification selector will highlight in red my other controls. But not the RadMaskedTextBox. To reproduce: Sample Silverlight app is attached to the internal description.