fix: close #1770

Author: NaBian

src/Net_40/HandyControl_Net_40/Themes/Theme.xaml

@@ -10733,7 +10733,6 @@
 		<Setter Property="BorderBrush" Value="{DynamicResource BorderBrush}" />
 		<Setter Property="Background" Value="{DynamicResource RegionBrush}" />
 		<Setter Property="BorderThickness" Value="1" />
-		<Setter Property="Foreground" Value="White" />
 		<Setter Property="ItemContainerStyle" Value="{StaticResource TabItemStyle}" />
 		<Setter Property="Template">
 			<Setter.Value>

src/Shared/HandyControl_Shared/Themes/Styles/Base/TabControlBaseStyle.xaml

@@ -70,7 +70,6 @@
         <Setter Property="BorderBrush" Value="{DynamicResource BorderBrush}" />
         <Setter Property="Background" Value="{DynamicResource RegionBrush}" />
         <Setter Property="BorderThickness" Value="1" />
-        <Setter Property="Foreground" Value="White" />
         <Setter Property="ItemContainerStyle" Value="{StaticResource TabItemStyle}" />
         <Setter Property="Template">
             <Setter.Value>

src/Shared/HandyControl_Shared/Themes/Theme.xaml

@@ -10852,7 +10852,6 @@
 		<Setter Property="BorderBrush" Value="{DynamicResource BorderBrush}" />
 		<Setter Property="Background" Value="{DynamicResource RegionBrush}" />
 		<Setter Property="BorderThickness" Value="1" />
-		<Setter Property="Foreground" Value="White" />
 		<Setter Property="ItemContainerStyle" Value="{StaticResource TabItemStyle}" />
 		<Setter Property="Template">
 			<Setter.Value>