Не знаю, является ли это именно тем, что вам нужно, но вы можете добавить этот шаблон данных и стиль в свой словарь ресурсов, чтобы отформатировать TabControl
с плоским стилем ...
<ControlTemplate x:Key="TabItemTemplate" TargetType="{x:Type TabItem}">
<Border Cursor="Hand" x:Name="tab" Background="White" BorderThickness="1,1,1,0" BorderBrush="Black" Padding="5">
<Grid>
<ContentPresenter x:Name="contentPresenter" ContentSource="Header"
TextBlock.Foreground="Black"
VerticalAlignment="Center"
HorizontalAlignment="Left"/>
</Grid>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsSelected" Value="False">
<Setter TargetName="tab" Property="Background" Value="Gray"/>
<Setter TargetName="tab" Property="BorderBrush" Value="Black"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsSelected" Value="False" />
<Condition Property="IsMouseOver" Value="True"/>
</MultiTrigger.Conditions>
<MultiTrigger.Setters>
<Setter TargetName="tab" Property="BorderBrush" Value="White"/>
<Setter TargetName="tab" Property="BorderThickness" Value="1,1,1,0"/>
</MultiTrigger.Setters>
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<Style TargetType="{x:Type TabControl}">
<Setter Property="Background" Value="White"/>
<Setter Property="BorderBrush" Value="Black"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TabControl}">
<Grid ClipToBounds="true" SnapsToDevicePixels="true" KeyboardNavigation.TabNavigation="Local">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<TabPanel x:Name="HeaderPanel" IsItemsHost="true" Margin="2,2,2,0" Grid.Row="0" KeyboardNavigation.TabIndex="1" Panel.ZIndex="1"/>
<Border x:Name="ContentPanel" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" KeyboardNavigation.DirectionalNavigation="Contained" Grid.Row="1" KeyboardNavigation.TabIndex="2" KeyboardNavigation.TabNavigation="Local">
<ContentPresenter x:Name="PART_SelectedContentHost" ContentSource="SelectedContent" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Border>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="{x:Type TabItem}">
<Setter Property="Template" Value="{StaticResource TabItemTemplate}" />
</Style>