Artemis/src/Artemis.UI.Shared/Styles/Controls/DataModelPickerButton.axaml

<Styles xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:controls="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia"
        xmlns:dataModelPicker="clr-namespace:Artemis.UI.Shared.DataModelPicker"
        xmlns:gradientPicker="clr-namespace:Artemis.UI.Shared.Controls.GradientPicker">
    <Design.PreviewWith>
        <Border Padding="20" Width="200">
            <StackPanel Spacing="5">
                <dataModelPicker:DataModelPickerButton />
                <gradientPicker:GradientPickerButton />
            </StackPanel>
        </Border>
    </Design.PreviewWith>

    <Style Selector="FlyoutPresenter.data-model-picker-presenter">
        <Setter Property="MaxWidth" Value="1200" />
        <Setter Property="MaxHeight" Value="1200" />
        <Setter Property="Background" Value="{DynamicResource SolidBackgroundFillColorBaseBrush}" />
        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Hidden" />
        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Hidden" />
    </Style>

    <Style Selector="dataModelPicker|DataModelPickerButton">
        <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrush}" />
        <Setter Property="MinHeight" Value="{DynamicResource TextControlThemeMinHeight}" />
        <Setter Property="MinWidth" Value="{DynamicResource TextControlThemeMinWidth}" />
        <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
        <Setter Property="Template">
            <ControlTemplate>
                <controls:Button Name="MainButton"
                                 CornerRadius="{TemplateBinding CornerRadius}"
                                 BorderBrush="{TemplateBinding BorderBrush}"
                                 VerticalAlignment="{TemplateBinding VerticalAlignment}"
                                 HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
                                 Width="{TemplateBinding Width}"
                                 Height="{TemplateBinding Height}"
                                 HorizontalContentAlignment="Stretch">
                    <Grid ColumnDefinitions="*,Auto" HorizontalAlignment="Stretch">
                        <TextBlock Name="MainButtonLabel"
                                   Grid.Column="0"
                                   VerticalAlignment="Center"
                                   TextAlignment="Left"
                                   TextTrimming="CharacterEllipsis"/>
                        <TextBlock Name="ChevronTextBlock"
                                   Grid.Column="1"
                                   FontFamily="{DynamicResource SymbolThemeFontFamily}"
                                   FontSize="13"
                                   Text="&#xE70D;"
                                   VerticalAlignment="Center"
                                   TextAlignment="Right"
                                   Padding="2 2 2 0"
                                   Margin="5 0" />
                    </Grid>
                </controls:Button>
            </ControlTemplate>
        </Setter>
    </Style>
</Styles>