Minor hack! Prevent double-click on tab (control) while animating

Without this hack, if the user double-clicks on a tab that is partially out of view, it will not scroll fully into view (with the desired additional "padding"). It seems to stop the animation prematurely and leave the TabControl headers in a undesirable state. This minor hack prevents this behavior.

Author: nicolaihenriksen

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

@@ -138,6 +138,11 @@ private void AssociatedObject_ScrollChanged(object sender, ScrollChangedEventArg
         double newValue = e.HorizontalOffset;
 
         _isAnimatingScroll = true;
+
+        // HACK: Temporarily disable user interaction while the animated scroll is ongoing. This prevents the double-click of a tab stopping the animation prematurely.
+        bool originalIsHitTestVisibleValue = TabControl.IsHitTestVisible;
+        TabControl.SetCurrentValue(FrameworkElement.IsHitTestVisibleProperty, false);
+
         AssociatedObject.ScrollToHorizontalOffset(originalValue);
         Debug.WriteLine($"Initiating animated scroll from {originalValue} to {newValue}. Change is: {e.HorizontalChange}");
         DoubleAnimation scrollAnimation = new(originalValue, newValue, new Duration(TimeSpan.FromMilliseconds(250)));
@@ -146,6 +151,9 @@ private void AssociatedObject_ScrollChanged(object sender, ScrollChangedEventArg
             Debug.WriteLine("Animation completed");
             _desiredScrollStart = null;
             _isAnimatingScroll = false;
+
+            // HACK: Set the hit test visibility back to its original value
+            TabControl.SetCurrentValue(FrameworkElement.IsHitTestVisibleProperty, originalIsHitTestVisibleValue);
         };
         AssociatedObject.BeginAnimation(TabControlHeaderScrollBehavior.CustomHorizontalOffsetProperty, scrollAnimation);
     }