Merge pull request #1059 from IbraheemOsama/GridSplitterFocusTrap

Grid splitter focus trap

Author: deltakosh

Microsoft.Toolkit.Uwp.UI.Controls/GridSplitter/GridSplitter.Events.cs

@@ -95,7 +95,7 @@ private void Gripper_KeyDown(object sender, KeyRoutedEventArgs e)
                 return;
             }
 
-            if (gripper.ResizeDirection == GridSplitter.GridResizeDirection.Rows)
+            if (gripper.ResizeDirection == GridResizeDirection.Rows)
             {
                 if (e.Key == VirtualKey.Up)
                 {

Microsoft.Toolkit.Uwp.UI.Controls/GridSplitter/GridSplitterGripper.cs

@@ -10,9 +10,6 @@
 // THE CODE OR THE USE OR OTHER DEALINGS IN THE CODE.
 // ******************************************************************
 
-using System;
-using Windows.System;
-using Windows.UI.Core;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Media;
@@ -31,10 +28,6 @@ internal class GridSplitterGripper : ContentControl
 
         public GridSplitter.GridResizeDirection ResizeDirection { get; private set; }
 
-        internal Action<double> OnKeyboardHorizontalMoveAction { get; set; }
-
-        internal Action<double> OnKeyboardVerticalMoveAction { get; set; }
-
         internal Brush GripperForeground
         {
             set
@@ -55,6 +48,7 @@ internal GridSplitterGripper(GridSplitter.GridResizeDirection gridSplitterDirect
             VerticalContentAlignment = VerticalAlignment.Stretch;
             IsTabStop = true;
             UseSystemFocusVisuals = true;
+            IsFocusEngagementEnabled = true;
         }
 
         internal GridSplitterGripper(