ClassicAssist.Avalonia/ClassicAssist/Resources/LeftRightIconToggleButton.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:resources="clr-namespace:ClassicAssist.Shared.Resources;assembly=ClassicAssist.Shared">
    <ResourceDictionary.MergedDictionaries>
        <ResourceDictionary Source="Icons.xaml"/>
    </ResourceDictionary.MergedDictionaries>
    <Style x:Key="FocusVisual">
        <Setter Property="Control.Template">
            <Setter.Value>
                <ControlTemplate>
                    <Rectangle Margin="2" SnapsToDevicePixels="true" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <Style x:Key="LeftRightIconToggleButton" TargetType="{x:Type ToggleButton}">
        <Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
        <Setter Property="HorizontalContentAlignment" Value="Center"/>
        <Setter Property="VerticalContentAlignment" Value="Center"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ToggleButton}">
                    <Image>
                        <Image.Style>
                            <Style TargetType="{x:Type Image}">
                                <Style.Triggers>
                                    <DataTrigger Binding="{Binding IsChecked, RelativeSource={RelativeSource TemplatedParent}}" Value="True">
                                        <Setter Property="Source" Value="{DynamicResource RightChevron}"/>
                                        <Setter Property="ToolTip" Value="{x:Static resources:Strings.Show}"/>
                                    </DataTrigger>
                                    <DataTrigger Binding="{Binding IsChecked, RelativeSource={RelativeSource TemplatedParent}}" Value="False">
                                        <Setter Property="Source" Value="{DynamicResource LeftChevron}"/>
                                        <Setter Property="ToolTip" Value="{x:Static resources:Strings.Hide}"/>
                                    </DataTrigger>
                                </Style.Triggers>
                            </Style>
                        </Image.Style>
                    </Image>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>