VisualStateManager.GoToState with TabItem not working - wpf

Question

My tabitem is styled by a ResourceDictionary that has a VisualState named Flashing.
I want to do something like this, but its not working.
public static void FlashTab(TabItem tbi)
{
bool thisReturnsFalse = VisualStateManager.GoToState(tbi, "Flashing", true);
}
The XAML
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Color x:Key="TabBrush0">#7F605F5F</Color>
<Color x:Key="TabBrush01">#7F605F5F</Color>
<Color x:Key="TabBrush02">#7F605F5F</Color>
<Color x:Key="TabBrush03">#7F605F5F</Color>
<Color x:Key="TabBrush04">#7F605F5F</Color>
<Color x:Key="TabBrush1">#7F7E7E7E</Color>
<Color x:Key="TabBrush2">#7FFDFDFD</Color>
<Color x:Key="TabBrush3">#7FFFFFFF</Color>
<Color x:Key="TabBrush4">#BFFFFFFF</Color>
<Color x:Key="TabBrush5">#F2FFFFFF</Color>
<Color x:Key="TabBrush6">#FF6096E5</Color>
<Color x:Key="TabBrush7">#FF9B7C35</Color>
<Color x:Key="TabBrush8">#FFB0BAA1</Color>
<Color x:Key="TabBrush10">White</Color>
<Color x:Key="Foreground">#FF000000</Color>
<Color x:Key="MouseOverColor">Purple</Color>
<Color x:Key="SelectedColor">Blue</Color>
<SolidColorBrush x:Key="ForegroundBrush" Color="{DynamicResource Foreground}" />
<Style TargetType="{x:Type TabItem}" >
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TabItem}">
<Grid Margin="1,0,1,0" >
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal"/>
<VisualState x:Name="MouseOver">
<Storyboard>
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="InnerRectangleMouseOver">
<EasingDoubleKeyFrame KeyTime="0" Value=".2"/>
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Selected">
<Storyboard>
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="InnerRectangleSelected">
<EasingDoubleKeyFrame KeyTime="0" Value=".2"/>
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Flashing" >
<Storyboard>
<DoubleAnimation
Storyboard.TargetName="GlassCube"
Storyboard.TargetProperty="Opacity"
From="0.0"
To="1.0"
Duration="0:0:0.33"
AutoReverse="True"
RepeatBehavior="Forever"/>
</Storyboard>
</VisualState>
<VisualState x:Name="Disabled"/>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Rectangle x:Name="InnerRectangleMouseOver" Margin="1,1,1,1" RadiusY="5" RadiusX="5" StrokeThickness="3" Opacity="0">
<Rectangle.Effect>
<BlurEffect/>
</Rectangle.Effect>
<Rectangle.Fill>
<LinearGradientBrush EndPoint="0.5,1" MappingMode="RelativeToBoundingBox" StartPoint="0.5,0">
<GradientStop Color="{DynamicResource MouseOverColor}" Offset="0.228"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<Rectangle x:Name="InnerRectangleSelected" Margin="1,1,1,1" RadiusY="5" RadiusX="5" StrokeThickness="3" Opacity="0">
<Rectangle.Effect>
<BlurEffect/>
</Rectangle.Effect>
<Rectangle.Fill>
<LinearGradientBrush EndPoint="0.5,1" MappingMode="RelativeToBoundingBox" StartPoint="0.5,0">
<GradientStop Color="{DynamicResource SelectedColor}" Offset="0.228"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<Rectangle x:Name="InnerRectangle" Margin="1,1,1,1" RadiusY="5" RadiusX="5" StrokeThickness="3" >
<Rectangle.Effect>
<BlurEffect/>
</Rectangle.Effect>
<Rectangle.Stroke>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="{DynamicResource Brush1}" Offset="1"/>
<GradientStop Color="{DynamicResource Brush0}"/>
</LinearGradientBrush>
</Rectangle.Stroke>
<Rectangle.Fill>
<LinearGradientBrush EndPoint="0.5,1" MappingMode="RelativeToBoundingBox" StartPoint="0.5,0">
<GradientStop Color="{DynamicResource Brush13}" Offset="0.228"/>
<GradientStop Color="{DynamicResource Brush7}"/>
<GradientStop Color="{DynamicResource Brush7}" Offset="0.823"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<Rectangle x:Name="GlassCube" Margin="1,1,1,1" RadiusY="5" RadiusX="5" StrokeThickness="3" Opacity="1">
<Rectangle.Stroke>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="{DynamicResource Brush4}"/>
<GradientStop Color="{DynamicResource Brush4}"/>
<GradientStop Color="{DynamicResource Brush6}" Offset="0.254"/>
<GradientStop Color="{DynamicResource Brush5}" Offset="0.401"/>
</LinearGradientBrush>
</Rectangle.Stroke>
<Rectangle.OpacityMask>
<RadialGradientBrush>
<GradientStop Color="{DynamicResource Brush11}" Offset="0"/>
<GradientStop Color="{DynamicResource Brush13}" Offset="1"/>
</RadialGradientBrush>
</Rectangle.OpacityMask>
<Rectangle.Fill>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="{DynamicResource Brush12}"/>
<GradientStop Color="{DynamicResource Brush7}" Offset="0.47"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<ContentPresenter HorizontalAlignment="Center" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="Center" ContentSource="Header" >
<TextBlock.Foreground>
<SolidColorBrush Color="{DynamicResource Foreground}"/>
</TextBlock.Foreground>
</ContentPresenter>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>

Answer 1

The TabItem will flash when you merge the ResourceDictionary into the Window.Resources of the TabControl's parent window (the ResourceDictionary is in ResourceDictionary.xaml here):
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="ResourceDictionary.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Window.Resources>
and when you fix the OpacityMask of the GlassCuberectangle. I've commented it out and it happily flashes:
<Rectangle x:Name="GlassCube" Margin="1,1,1,1" RadiusY="5" RadiusX="5" StrokeThickness="3" Opacity="1">
<Rectangle.Stroke>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="{DynamicResource TabBrush4}"/>
<GradientStop Color="{DynamicResource TabBrush4}"/>
<GradientStop Color="{DynamicResource TabBrush6}" Offset="0.254"/>
<GradientStop Color="{DynamicResource TabBrush5}" Offset="0.401"/>
</LinearGradientBrush>
</Rectangle.Stroke>
<!--<Rectangle.OpacityMask>
<RadialGradientBrush>
<GradientStop Color="{DynamicResource TabBrush11}" Offset="0"/>
<GradientStop Color="{DynamicResource TabBrush13}" Offset="1"/>
</RadialGradientBrush>
</Rectangle.OpacityMask>-->
<Rectangle.Fill>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="{DynamicResource TabBrush12}"/>
<GradientStop Color="{DynamicResource TabBrush7}" Offset="0.47"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
EDIT: There is one more thing to mention concerning the keys of the color resources. You define them with keys TabBrush1, TabBrush2 etc. but when you use them in Color="{DynamicResource ...}", you always use keys Brush1, Brush2 etc.