Flow.Launcher/Flow.Launcher/HotkeyControl.axaml

<UserControl
    x:Class="Flow.Launcher.HotkeyControl"
    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:launcher="clr-namespace:Flow.Launcher"
    Height="24"
    d:DesignHeight="300"
    d:DesignWidth="300"
    mc:Ignorable="d"
    x:DataType="launcher:HotkeyControl">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="200" />
        </Grid.ColumnDefinitions>
        <Popup
            x:Name="popup"
            Placement="Top"
            PlacementTarget="{Binding ElementName=tbHotkey}"
            VerticalOffset="-5">
            <Border
                Width="140"
                Height="30"
                Background="{DynamicResource Color01B}"
                BorderBrush="{DynamicResource Color21B}"
                BorderThickness="1"
                CornerRadius="4">
                <TextBlock
                    x:Name="tbMsg"
                    Margin="0,0,0,0"
                    HorizontalAlignment="Center"
                    VerticalAlignment="Center"
                    FontSize="13"
                    FontWeight="SemiBold"
                    Foreground="{DynamicResource Color05B}"
                    Text="{DynamicResource flowlauncherPressHotkey}"/>
            </Border>
        </Popup>

        <TextBox
            x:Name="tbHotkey"
            Margin="0,0,18,0"
            VerticalContentAlignment="Center"
            LostFocus="tbHotkey_LostFocus"
            KeyDown="TbHotkey_OnPreviewKeyDown"
            TabIndex="100" />
    </Grid>
</UserControl>