Thank-you for the quick responses,I still have a weird feeling that something else is wrong because that is exactly what I have. The ToggleVisibilityAction works, but the ToggleCollapseAction does not. Same result, just without the fancy fade away. Is there a limit to what you can put inside a CollapsiblePanel?
<Grid HorizontalAlignment="Left" VerticalAlignment="Top" Margin="10">
<sl:CollapsiblePanel x:Name="cpThemes" IsExpanded="True"
VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
<Border x:Name="borderThemes" Background="#99072C6E" BorderThickness="1" CornerRadius="5"
HorizontalAlignment="Left" VerticalAlignment="Top"
Padding="5" BorderBrush="Black" >
<Border.Effect>
<DropShadowEffect/>
</Border.Effect>
<Grid>
<TextBlock Text="Themes" Foreground="WhiteSmoke" FontWeight="Bold" Grid.Row="0"/>
<ListBox x:Name="MyLayers" ItemsSource="{Binding Layers, ElementName=MyMap}" Margin="0,20,0,0">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox IsChecked="{Binding Visible, Mode=TwoWay}" />
<Slider Margin="-5,0,0,0" Minimum="0" Maximum="1" Width="60"
Value="{Binding Opacity, Mode=TwoWay}" Height="18" />
<TextBlock Text="{Binding ID, Mode=OneWay}" Margin="5,0,0,0" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Border>
</sl:CollapsiblePanel>
<Image Source="Images/Layers-32.png" HorizontalAlignment="Left" VerticalAlignment="Top"
Stretch="Fill" Height="40" Width="40" Margin="10">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseLeftButtonDown">
<!--<slActions:ToggleCollapseAction TargetName="cpThemes"/>-->
<slActions:ToggleVisibilityAction TargetName="cpThemes"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</Image>
</Grid>