Saradomin-Launcher/Saradomin/Views/Windows/MainWindow.axaml

<glitonea:WindowEx xmlns="https://github.com/avaloniaui"
                   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                   xmlns:glitonea="clr-namespace:Glitonea;assembly=Glitonea"
                   xmlns:mvvm="clr-namespace:Glitonea.Mvvm;assembly=Glitonea"
                   xmlns:vm="clr-namespace:Saradomin.ViewModel.Windows"
                   xmlns:controls="clr-namespace:Saradomin.Views.Controls"
                   Width="800"
                   Height="500"
                   SystemDecorations="None"
                   x:Class="Saradomin.Views.Windows.MainWindow"
                   Title="{Binding Title}"
                   DataContext="{mvvm:DataContextSource vm:MainWindowViewModel}"
                   WindowStartupLocation="CenterScreen"
                   Icon="{DynamicResource MainApplicationIcon}"
                   Name="MainWindow">
    <Border BorderThickness="2"
            BorderBrush="#3E3529">
        <Grid RowDefinitions="24,*,32">
            <Grid Grid.Row="0"
                  Background="#3E3529"
                  PointerPressed="TitleBar_MouseDown"
                  ColumnDefinitions="Auto,*,Auto">

                <TextBlock Grid.Column="1"
                           Grid.ColumnSpan="3"
                           HorizontalAlignment="Center"
                           VerticalAlignment="Center"
                           Text="{Binding #MainWindow.Title}"
                           FontSize="14"
                           Foreground="#F2C954"
                           FontFamily="Open Sans"
                           FontWeight="Light" />

                <Button Grid.Column="2"
                        Classes="CloseButton"
                        Command="{Binding ExitApplication}" />
            </Grid>

            <Grid Grid.Row="1"
                  Grid.ZIndex="1"
                  Margin="0,2,4,0"
                  VerticalAlignment="Top"
                  HorizontalAlignment="Right"
                  ColumnDefinitions="Auto,Auto,Auto,Auto">
                <Button Grid.Column="0"
                        Classes="OutsideNavigator"
                        Content="latest news"
                        CornerRadius="8,0,0,8"
                        Command="{Binding LaunchPage}"
                        CommandParameter="news" />

                <Button Grid.Column="1"
                        Classes="OutsideNavigator"
                        Content="found a bug?"
                        Command="{Binding LaunchPage}"
                        CommandParameter="issues" />

                <Button Grid.Column="2"
                        Classes="OutsideNavigator"
                        Content="hi-scores"
                        Command="{Binding LaunchPage}"
                        CommandParameter="hiscores" />

                <Button Grid.Column="3"
                        Classes="OutsideNavigator"
                        Content="discord"
                        CornerRadius="0,8,8,0"
                        Command="{Binding LaunchPage}"
                        CommandParameter="discord" />
            </Grid>

            <TabControl Grid.Row="1"
                        Grid.RowSpan="1"
                        Classes="PageSelector"
                        Background="#A1855C"
                        BorderBrush="#312D25">
                <TabItem Header="what's new"
                         CornerRadius="0,0,0,8"
                         HorizontalContentAlignment="Center"
                         Width="95">
                    <Border CornerRadius="6,6,0,0"
                            Margin="4,0,4,0"
                            BorderBrush="#7D694E"
                            BorderThickness="1,1,1,0"
                            Background="#998468"
                            ClipToBounds="True">
                        <ScrollViewer HorizontalAlignment="Stretch"
                                      VerticalScrollBarVisibility="Visible"
                                      HorizontalScrollBarVisibility="Hidden"
                                      ClipToBounds="True">
                            <HtmlLabel Name="HtmlView"
                                       AutoSize="False"
                                       AutoSizeHeightOnly="True"
                                       Margin="4,0,4,4"
                                       Width="750"
                                       VerticalAlignment="Stretch" />
                        </ScrollViewer>
                    </Border>
                </TabItem>

                <TabItem Header="settings"
                         CornerRadius="0,0,8,0"
                         HorizontalContentAlignment="Center"
                         Width="95">
                    <Border CornerRadius="6,6,0,0"
                            Margin="4,0,4,0"
                            BorderBrush="#7D694E"
                            BorderThickness="1,1,1,0"
                            Background="#998468">
                        <ScrollViewer VerticalScrollBarVisibility="Visible"
                                      HorizontalScrollBarVisibility="Hidden">
                            <controls:SettingsView VerticalAlignment="Stretch" />
                        </ScrollViewer>
                    </Border>
                </TabItem>
            </TabControl>

            <Border Grid.Row="2"
                  Background="#A1855C"
                  BorderBrush="#7D694E"
                  BorderThickness="0,1,0,0">
                <TextBlock Text="And here I would place a progress bar integrated with a button. IF I HAD ONE."
                           Foreground="#3E3529"
                           HorizontalAlignment="Center"
                           VerticalAlignment="Center" />
            </Border>
        </Grid>
    </Border>
</glitonea:WindowEx>