Disabled items in ComboBox souldn't be selectable with arrow keys.

src/Avalonia.Controls/ComboBox.cs

@@ -453,42 +453,18 @@ private void SelectFocusedItem()
 
         private void SelectNext()
         {
-            int next = SelectedIndex + 1;
-
-            if (next >= ItemCount)
+            if (ItemCount >= 1)
             {
-                if (WrapSelection == true)
-                {
-                    next = 0;
-                }
-                else
-                {
-                    return;
-                }
+                MoveSelection(NavigationDirection.Next, WrapSelection);
             }
-
-
-
-            SelectedIndex = next;
         }
 
         private void SelectPrev()
         {
-            int prev = SelectedIndex - 1;
-
-            if (prev < 0)
+            if (ItemCount >= 1)
             {
-                if (WrapSelection == true)
-                {
-                    prev = ItemCount - 1;
-                }
-                else
-                {
-                    return;
-                }
+                MoveSelection(NavigationDirection.Previous, WrapSelection);
             }
-
-            SelectedIndex = prev;
         }
     }
 }

src/Avalonia.Controls/ItemsControl.cs

@@ -508,7 +508,6 @@ private void UpdatePseudoClasses(int itemCount)
             do
             {
                 result = container.GetControl(direction, c, wrap);
-                from = from ?? result;
 
                 if (result != null &&
                     result.Focusable &&

src/Avalonia.Controls/StackPanel.cs

@@ -123,7 +123,7 @@ public Orientation Orientation
                     index = Children.Count - 1;
                     break;
                 case NavigationDirection.Next:
-                    if (index != -1) ++index;
+                    ++index;
                     break;
                 case NavigationDirection.Previous:
                     if (index != -1) --index;

tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs

@@ -36,6 +36,81 @@ public void Clicking_On_Control_Toggles_IsDropDownOpen()
             Assert.False(target.IsDropDownOpen);
         }
 
+        [Fact]
+        public void WrapSelection_Should_Work()
+        {
+            using (UnitTestApplication.Start(TestServices.RealFocus))
+            {
+                var items = new[]
+                {
+                    new ComboBoxItem() { Content = "bla" },
+                    new ComboBoxItem() { Content = "dd" },
+                    new ComboBoxItem() { Content = "sdf", IsEnabled = false }
+                };
+                var target = new ComboBox
+                {
+                    Items = items,
+                    Template = GetTemplate(),
+                    WrapSelection = true
+                };
+                var root = new TestRoot(target);
+                target.ApplyTemplate();
+                target.Presenter.ApplyTemplate();
+                target.Focus();
+                Assert.Equal(target.SelectedIndex, -1);
+                Assert.True(target.IsFocused);
+                target.RaiseEvent(new KeyEventArgs
+                {
+                    RoutedEvent = InputElement.KeyDownEvent,
+                    Key = Key.Up,
+                });
+                Assert.Equal(target.SelectedIndex, 1);
+                target.RaiseEvent(new KeyEventArgs
+                {
+                    RoutedEvent = InputElement.KeyDownEvent,
+                    Key = Key.Down,
+                });
+                Assert.Equal(target.SelectedIndex, 0);
+            }
+        }
+
+        [Fact]
+        public void Focuses_Next_Item_On_Key_Down()
+        {
+            using (UnitTestApplication.Start(TestServices.RealFocus))
+            {
+                var items = new[]
+                {
+                    new ComboBoxItem() { Content = "bla" },
+                    new ComboBoxItem() { Content = "dd", IsEnabled = false },
+                    new ComboBoxItem() { Content = "sdf" }
+                };
+                var target = new ComboBox
+                {
+                    Items = items,
+                    Template = GetTemplate()
+                };
+                var root = new TestRoot(target);
+                target.ApplyTemplate();
+                target.Presenter.ApplyTemplate();
+                target.Focus();
+                Assert.Equal(target.SelectedIndex, -1);
+                Assert.True(target.IsFocused);
+                target.RaiseEvent(new KeyEventArgs
+                {
+                    RoutedEvent = InputElement.KeyDownEvent,
+                    Key = Key.Down,
+                });
+                Assert.Equal(target.SelectedIndex, 0);
+                target.RaiseEvent(new KeyEventArgs
+                {
+                    RoutedEvent = InputElement.KeyDownEvent,
+                    Key = Key.Down,
+                });
+                Assert.Equal(target.SelectedIndex, 2);
+            }
+        }
+
         [Fact]
         public void SelectionBoxItem_Is_Rectangle_With_VisualBrush_When_Selection_Is_Control()
         {