Add TabAssist.AnimateTabScrolling to toggle tab switch animation feature

Defaulted to True in a style setter allowing for easy override at the call site.

Author: nicolaihenriksen

src/MaterialDesignThemes.Wpf/Behaviors/Internal/TabControlHeaderScrollBehavior.cs

@@ -132,7 +132,11 @@ protected override void OnDetaching()
     private void AssociatedObject_ScrollChanged(object sender, ScrollChangedEventArgs e)
     {
         Debug.WriteLine($"ContentHorizontalOffset: {AssociatedObject.ContentHorizontalOffset}, HorizontalOffset: {e.HorizontalOffset}, HorizontalChange: {e.HorizontalChange}, ViewportWidth: {e.ViewportWidth}, ExtentWidth: {e.ExtentWidth}");
-        if (_isAnimatingScroll || _desiredScrollStart is not { } desiredOffsetStart) return;
+        bool useAnimation = TabAssist.GetAnimateTabScrolling(TabControl);
+        if (!useAnimation)
+            return;
+        if ( _isAnimatingScroll || _desiredScrollStart is not { } desiredOffsetStart)
+            return;
 
         double originalValue = desiredOffsetStart;
         double newValue = e.HorizontalOffset;

src/MaterialDesignThemes.Wpf/TabAssist.cs

@@ -69,4 +69,13 @@ public static void SetHeaderBehavior(DependencyObject obj, TabControlHeaderBehav
     public static readonly DependencyProperty HeaderBehaviorProperty =
         DependencyProperty.RegisterAttached("HeaderBehavior", typeof(TabControlHeaderBehavior), typeof(TabAssist),
             new PropertyMetadata(TabControlHeaderBehavior.Scrolling));
+
+    public static bool GetAnimateTabScrolling(DependencyObject obj)
+        => (bool)obj.GetValue(AnimateTabScrollingProperty);
+
+    public static void SetAnimateTabScrolling(DependencyObject obj, bool value)
+        => obj.SetValue(AnimateTabScrollingProperty, value);
+
+    public static readonly DependencyProperty AnimateTabScrollingProperty =
+        DependencyProperty.RegisterAttached("AnimateTabScrolling", typeof(bool), typeof(TabAssist), new PropertyMetadata(false));
 }

src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.TabControl.xaml

@@ -233,6 +233,7 @@
     <Setter Property="wpf:ElevationAssist.Elevation" Value="Dp4" />
     <Setter Property="wpf:RippleAssist.Feedback" Value="{DynamicResource MaterialDesign.Brush.Button.Ripple}" />
     <Setter Property="wpf:TabAssist.HasUniformTabWidth" Value="False" />
+    <Setter Property="wpf:TabAssist.AnimateTabScrolling" Value="True" />
 
     <Style.Triggers>
       <Trigger Property="wpf:TabAssist.HeaderBehavior" Value="Wrapping">