Problem with a multitrigger

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C#

XAML

WPF

trigger

Hello everyone,
I have a problem with my multitrigger and I don't know what is wrong.

This is my multitrigger:

<MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsChecked" Value="True" />
                                    <Condition Property="IsEnabled" Value="False" />
                                </MultiTrigger.Conditions>
                                <MultiTrigger.Setters>
                                    <Setter Property="Background" TargetName="Innerborder" Value="#FFFF0000"/>
                                    <Setter Property="BorderBrush" TargetName="Innerborder" Value="#FF295B2E"/>
                                </MultiTrigger.Setters>
                            </MultiTrigger>

It simply doesn't work and I don't know why.

At another place in my code I have a similar multitrigger which works perfectly fine.

I hope you can help me

What I have tried:

Copy&Pasted my other working multitrigger (with editing the TargetName)