ryujinx/Ryujinx.Ava/UI/Windows/ContentDialogOverlayWindow.axaml

<window:StyleableWindow
    xmlns="https://github.com/avaloniaui"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:ui="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia"
    xmlns:window="clr-namespace:Ryujinx.Ava.UI.Windows"
    mc:Ignorable="d"
    d:DesignWidth="800"
    d:DesignHeight="450"
    x:Class="Ryujinx.Ava.UI.Windows.ContentDialogOverlayWindow"
    Title="ContentDialogOverlayWindow"
    Focusable="False">
    <window:StyleableWindow.Styles>
        <Style Selector="ui|ContentDialog /template/ Panel#LayoutRoot">
            <Setter Property="Background"
                    Value="Transparent" />
        </Style>
    </window:StyleableWindow.Styles>
    <ui:ContentDialog Name="ContentDialog"
                      IsPrimaryButtonEnabled="True"
                      IsSecondaryButtonEnabled="True"
                      IsVisible="False"
                      Focusable="True"/>
</window:StyleableWindow>