'[Unknown]' property does not point to a DependencyObject in path '(0).(1)[0].(2)'

[mehdi mahbobi]

سلام به همه ی دوستان.
من در نرم افزار blend استایلی رو برای button ساختم که تو برنامه ی اصلی که میخوام ازش استفاده کنم desigin time error این شکلی میده:

'[Unknown]' property does not point to a DependencyObject in path '(0).(1)[0].(2)' 

البته در زما ن اجرا مشکلی پیش نمی یاد و به درستی کار میکنه. خوب کد استایل بصورت زیر .دوستان اگه میتونن
راهنمایی کنن.

<ResourceDictionary

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <Style x:Key="ButtonStyle2" TargetType="{x:Type Button}">

        <Setter Property="Template">

            <Setter.Value>

                <ControlTemplate TargetType="{x:Type Button}">

                    <Grid>

                        <VisualStateManager.VisualStateGroups>

                            <VisualStateGroup x:Name="CommonStates">

                                <VisualState x:Name="Normal">

                                    <Storyboard>

                                        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background).(Gra  dientBrush.GradientStops)[0].(GradientStop.Color)" Storyboard.TargetName="border">

                                            <EasingColorKeyFrame KeyTime="0" Value="#FF37E22A"/>

                                        </ColorAnimationUsingKeyFrames>

                                    </Storyboard>

                                </VisualState>

                                <VisualState x:Name="MouseOver">

                                    <Storyboard>

                                        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background).(Gra  dientBrush.GradientStops)[0].(GradientStop.Color)" Storyboard.TargetName="border">

                                            <EasingColorKeyFrame KeyTime="0" Value="#FF22CA14"/>

                                            <EasingColorKeyFrame KeyTime="0:0:0.3" Value="#FF1AF706"/>

                                        </ColorAnimationUsingKeyFrames>

                                        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background).(Gra  dientBrush.GradientStops)[1].(GradientStop.Color)" Storyboard.TargetName="border">

                                            <EasingColorKeyFrame KeyTime="0:0:0.3" Value="#FF1FB412"/>

                                        </ColorAnimationUsingKeyFrames>

                                        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background).(Gra  dientBrush.GradientStops)[2].(GradientStop.Color)" Storyboard.TargetName="border">

                                            <EasingColorKeyFrame KeyTime="0:0:0.3" Value="#FF37FD26"/>

                                        </ColorAnimationUsingKeyFrames>

                                        <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background).(Gra  dientBrush.GradientStops)[2].(GradientStop.Offset)" Storyboard.TargetName="border">

                                            <EasingDoubleKeyFrame KeyTime="0:0:0.3" Value="0.5"/>

                                        </DoubleAnimationUsingKeyFrames>

                                    </Storyboard>

                                </VisualState>

                                <VisualState x:Name="Pressed"/>

                                <VisualState x:Name="Disabled"/>

                            </VisualStateGroup>

                        </VisualStateManager.VisualStateGroups>

                        <Border x:Name="border" BorderBrush="Black" BorderThickness="1" CornerRadius="7">

                            <Border.Background>

                                <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">

                                    <GradientStop Color="#FF11680A" Offset="0"/>

                                    <GradientStop Color="#FF13FF00" Offset="1"/>

                                    <GradientStop Color="#FF168F0C" Offset="0.483"/>

                                </LinearGradientBrush>

                            </Border.Background>

                        </Border>

                        <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>

                    </Grid>

                    <ControlTemplate.Triggers>

                        <Trigger Property="IsFocused" Value="True"/>

                        <Trigger Property="IsDefaulted" Value="True"/>

                        <Trigger Property="IsMouseOver" Value="True"/>

                        <Trigger Property="IsPressed" Value="True"/>

                        <Trigger Property="IsEnabled" Value="False"/>

                    </ControlTemplate.Triggers>

                </ControlTemplate>

            </Setter.Value>

        </Setter>

    </Style>

    <!-- Resource dictionary entries should be defined here. -->

</ResourceDictionary>