some silverlight controls doesn't show

See more:

Silverlight5

Hi I'm beginner in silver light.
when i drag some controls (like button,textbox) on a grid,silver light doesn't show it
i tried on Firefox,chrome and IE result is same
this is my xaml code

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation" 
    xmlns:uriMapper="clr-namespace:System.Windows.Navigation;assembly=System.Windows.Controls.Navigation"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
    x:Class="robo_panel.MainPage" 
    mc:Ignorable="d" d:DesignWidth="1024" d:DesignHeight="768">

    <Grid x:Name="LayoutRoot" Style="{StaticResource LayoutRootGridStyle}">

        <Grid x:Name="NavigationGrid" Style="{StaticResource NavigationGridStyle}" Height="Auto" VerticalAlignment="Stretch">
            <Grid.Background>
                <ImageBrush Stretch="Fill" ImageSource="vista1.jpg"/>
            </Grid.Background>

            <Border x:Name="BrandingBorder" Style="{StaticResource BrandingBorderStyle}"/>

            <Border x:Name="LinksBorder" Style="{StaticResource LinksBorderStyle}">
                <StackPanel x:Name="LinksStackPanel" Style="{StaticResource LinksStackPanelStyle}">

                    <Rectangle x:Name="Divider1" Style="{StaticResource DividerStyle}"/>

                </StackPanel>
            </Border>
            <TextBox HorizontalAlignment="Left" Margin="331,309,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="288" Height="43" Grid.RowSpan="5" Grid.ColumnSpan="5"/>

            <sdk:Label HorizontalAlignment="Center" Margin="638,309,266,416" VerticalAlignment="Center" Content="نام کاربری " FontFamily="B Koodak" FontSize="20" FontWeight="Bold"/>
            <sdk:Label HorizontalAlignment="Center" Margin="638,377,266,348" VerticalAlignment="Center" Content="رمز عبور" FontFamily="B Koodak" FontSize="20" FontWeight="Bold"/>
            <PasswordBox HorizontalAlignment="Left" Margin="331,377,405,348" VerticalAlignment="Top" Width="288" Height="43"/>

        </Grid>

    </Grid>

</UserControl>