Display Error using Datatemplate - wpf

Question

today you helped me with Need multiple styles dependent on Listboxitem
But now i get a gray rectangle while drawing or moving the objects.
Picture with how it should look like, and how it looks like when iam drawing a line:
https://drive.google.com/file/d/0B_F04v1afwM5c0kteExsamlMcHM/edit?usp=sharing
here is the code i used:
<ListBox.Resources>
<DataTemplate DataType="{x:Type model:PathLine}">
<Path Stroke="{Binding ObjectColor}" StrokeThickness="{Binding StrokeThickness}" Data="{Binding PathGeometryData}" x:Name="PathLine" Opacity="{Binding Opacity}" >
</Path>
</DataTemplate>
<DataTemplate DataType="{x:Type model:ImageObject}">
<Image Source="H:\Dropbox\WPF Projekte\Arena WPF\ArenaProgram\ArenaProgram\Pictures\tree1.png" Name="imgPic1" Width="100" Height="75" Stretch="Fill" VerticalAlignment="Top" />
</DataTemplate>
<Style TargetType="ListBoxItem">
<Style.Triggers>
<Trigger Property="IsSelected" Value="true">
<Setter Property="Effect">
<Setter.Value>
<DropShadowEffect Color="Crimson" ShadowDepth="3" BlurRadius="10" />
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</ListBox.Resources>
hope someone can help me :)

Answer 1

Aha! Finally, I know what you're talking about. :)
It seems to me that that (in my opinion, white) rectangle with a light crimson border is the ListBoxItem object. You added a Style that tells the ListBoxItem to display a crimson glow around its edge when it is selected, so that is what you are seeing. Try adding a Setter which sets the Background property to Transparent:
<Style TargetType="ListBoxItem">
<Setter Property="Background" Value="Transparent" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="true">
<Setter Property="Effect">
<Setter.Value>
<DropShadowEffect Color="Crimson" ShadowDepth="3" BlurRadius="10"/>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
If that doesn't work, you might think about removing the Trigger altogether.