# Other .NET Programming > Windows Presentation Foundation (WPF) & XAML forum >  Event Trigger only for parent expander, not for all

## Tweety_2020

I have a GroupBox which conatains an Expander and there is another expander inside the first one. So the first expander is a parent to the second one.

What I want to do is to put a blue border around the parent expander when parent expander is expanded and set it back to white, when it's collapsed. What I have works also, but the parent expander is not the only one which can do this. When I expand the child the event starts as well, which I don't want.

Can someone help me make the parent expander be the only one being able to start the event?

My code:



```
<GroupBox x:Name="ABC" Header="Something" Width="Auto" Margin="-800,35,-600,20" Grid.Column="1"  BorderBrush="White" FontFamily ="Century Gothic" FontSize="16"   >


                        <Expander x:Name="Kat_1" FontFamily="Century Gothic" FontSize="20" Header=" Funktion / Leitung"  IsExpanded="False" Foreground="#FF19194D" Visibility="Visible" Margin="10,10,875,792" Height="900">
                            <Expander.Effect>
                                <DropShadowEffect BlurRadius="5" ShadowDepth="2" />
                            </Expander.Effect>

                            <Expander.BorderBrush>
                                <LinearGradientBrush>
                                    <GradientStop />
                                    <GradientStop />
                                </LinearGradientBrush>
                            </Expander.BorderBrush>


                            <Expander.Triggers>
                                <EventTrigger RoutedEvent="Expander.Expanded" SourceName="Kat_1">

                                    <EventTrigger.Actions>
                                        <BeginStoryboard>
                                            <Storyboard TargetName="Kat_1" >
                                            <Storyboard TargetProperty="BorderBrush.GradientStops[0].Color" >
                                                <ColorAnimation From="White"
                                                            To="#FF19194D"
                                                            Duration="0:0:1"
                                                            AutoReverse="False" />

                                            </Storyboard>
                                            </Storyboard>
                                        </BeginStoryboard>

                                        <BeginStoryboard>
                                            <Storyboard TargetName="Kat_1" >
                                                <Storyboard TargetProperty="BorderBrush.GradientStops[1].Offset">
                                                    <DoubleAnimation From="0"
                                                             To="1"
                                                             Duration="0:0:1"
                                                             AutoReverse="False" />

                                                </Storyboard>
                                            </Storyboard>
                                        </BeginStoryboard>
                                    </EventTrigger.Actions>
                                </EventTrigger>

                                <EventTrigger RoutedEvent="Expander.Collapsed" SourceName="Kat_1">
                                    <EventTrigger.Actions>
                                        <BeginStoryboard>
                                            <Storyboard TargetName="Kat_1" >
                                                <Storyboard TargetProperty="BorderBrush.GradientStops[0].Color">
                                                    <ColorAnimation From="#FF19194D"
                                                            To="White"
                                                            Duration="0:0:1"
                                                            AutoReverse="False" />
                                                </Storyboard>
                                            </Storyboard>
                                        </BeginStoryboard>

                                        <BeginStoryboard>
                                            <Storyboard TargetName="Kat_1" >
                                                <Storyboard TargetProperty="BorderBrush.GradientStops[1].Offset">
                                                    <DoubleAnimation From="1"
                                                             To="0"`enter code here`
                                                             Duration="0:0:1"
                                                             AutoReverse="False" />
                                                </Storyboard>
                                            </Storyboard>
                                        </BeginStoryboard>
                                    </EventTrigger.Actions>
                                </EventTrigger>
                            </Expander.Triggers>
<Expander x:Name="Kat_1_1" FontFamily="Century Gothic" FontSize="20" Header=" Allgemein" IsExpanded="False" Foreground="#FF19194D" Visibility="Visible" Margin="30,10,10,0" Width="570">
    </Expander>                                      
  </Expander>
</GroupBox>
```

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