### Bug explanation <PackageReference Include="MaterialDesignThemes" Version="5.2.1" /> System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:(no path); DataItem=null; target element is 'VisualBrush' (HashCode=4839561); target property is 'Visual' (type 'Visual') Search the source code and locate the point <Grid.OpacityMask> <VisualBrush> <VisualBrush.Visual> <MultiBinding Converter="{x:Static converters:FirstNonNullConverter.Instance}"> <Binding ElementName="ContentCoverBorder" /> <Binding Source="{x:Static DependencyProperty.UnsetValue}" /> </MultiBinding> </VisualBrush.Visual> </VisualBrush> </Grid.OpacityMask> Not sure if it's correct ### Version 5.2.1