From 52762d7c02515474e88e300e41d859e58235fdd2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Dach?= <dach.bartlomiej@gmail.com>
Date: Tue, 20 Aug 2024 15:09:17 +0200
Subject: [PATCH 1/2] Add failing test case

---
 .../Visual/UserInterface/TestSceneTextBox.cs  | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/osu.Framework.Tests/Visual/UserInterface/TestSceneTextBox.cs b/osu.Framework.Tests/Visual/UserInterface/TestSceneTextBox.cs
index 511a99dca7..1242f984f3 100644
--- a/osu.Framework.Tests/Visual/UserInterface/TestSceneTextBox.cs
+++ b/osu.Framework.Tests/Visual/UserInterface/TestSceneTextBox.cs
@@ -932,6 +932,76 @@ public void TestTypingCancelsOngoingDragSelection()
             AddAssert("text selected by drag", () => textBox.SelectedText == "1");
         }
 
+        [Test]
+        public void TestTabbing()
+        {
+            AddStep("add textboxes", () =>
+            {
+                textBoxes.AddRange([
+                    new InsertableTextBox
+                    {
+                        Size = new Vector2(300, 40),
+                        Text = "first!",
+                        ReadOnly = false,
+                        TabbableContentContainer = textBoxes,
+                    },
+                    new InsertableTextBox
+                    {
+                        Size = new Vector2(300, 40),
+                        Text = "second!",
+                        ReadOnly = false,
+                        TabbableContentContainer = textBoxes,
+                    },
+                    new InsertableTextBox
+                    {
+                        Size = new Vector2(300, 40),
+                        Text = "third! (readonly)",
+                        ReadOnly = true,
+                        TabbableContentContainer = textBoxes,
+                    },
+                    new InsertableTextBox
+                    {
+                        Size = new Vector2(300, 40),
+                        Text = "fourth!",
+                        ReadOnly = false,
+                        TabbableContentContainer = textBoxes,
+                    }
+                ]);
+            });
+
+            AddStep("focus first textbox", () =>
+            {
+                InputManager.MoveMouseTo(textBoxes[0]);
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddStep("press tab", () => InputManager.Key(Key.Tab));
+            AddAssert("second textbox focused", () => textBoxes[1].HasFocus);
+
+            AddStep("press tab", () => InputManager.Key(Key.Tab));
+            AddAssert("readonly textbox skipped", () => textBoxes[3].HasFocus);
+
+            AddStep("press tab", () => InputManager.Key(Key.Tab));
+            AddAssert("first textbox focused", () => textBoxes[0].HasFocus);
+
+            AddStep("press shift-tab", () =>
+            {
+                InputManager.PressKey(Key.ShiftLeft);
+                InputManager.Key(Key.Tab);
+                InputManager.ReleaseKey(Key.ShiftLeft);
+            });
+            AddAssert("fourth textbox focused", () => textBoxes[3].HasFocus);
+
+            AddStep("hide second textbox", () => textBoxes[1].Alpha = 0);
+            AddStep("press shift-tab", () =>
+            {
+                InputManager.PressKey(Key.ShiftLeft);
+                InputManager.Key(Key.Tab);
+                InputManager.ReleaseKey(Key.ShiftLeft);
+            });
+            AddAssert("first textbox focused", () => textBoxes[0].HasFocus);
+        }
+
         private void prependString(InsertableTextBox textBox, string text)
         {
             InputManager.Keys(PlatformAction.MoveBackwardLine);

From c532d8a93977ff4f9f66cebfb6b09541ced5e4ee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Dach?= <dach.bartlomiej@gmail.com>
Date: Tue, 20 Aug 2024 15:11:22 +0200
Subject: [PATCH 2/2] Fix tabbable container not checking if its next tab stop
 is focusable

Closes https://github.com/ppy/osu/issues/29501.
---
 .../Graphics/Containers/TabbableContainer.cs        | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/osu.Framework/Graphics/Containers/TabbableContainer.cs b/osu.Framework/Graphics/Containers/TabbableContainer.cs
index 14c1335af2..9a49804fb6 100644
--- a/osu.Framework/Graphics/Containers/TabbableContainer.cs
+++ b/osu.Framework/Graphics/Containers/TabbableContainer.cs
@@ -44,13 +44,14 @@ protected override bool OnKeyDown(KeyDownEvent e)
             if (TabbableContentContainer == null || e.Key != Key.Tab)
                 return false;
 
-            var nextTab = nextTabStop(TabbableContentContainer, e.ShiftPressed);
-            if (nextTab != null) GetContainingFocusManager().AsNonNull().ChangeFocus(nextTab);
+            moveToNextTabStop(TabbableContentContainer, e.ShiftPressed);
             return true;
         }
 
-        private Drawable nextTabStop(CompositeDrawable target, bool reverse)
+        private void moveToNextTabStop(CompositeDrawable target, bool reverse)
         {
+            var focusManager = GetContainingFocusManager().AsNonNull();
+
             Stack<Drawable> stack = new Stack<Drawable>();
             stack.Push(target); // Extra push for circular tabbing
             stack.Push(target);
@@ -63,8 +64,8 @@ private Drawable nextTabStop(CompositeDrawable target, bool reverse)
 
                 if (!started)
                     started = ReferenceEquals(drawable, this);
-                else if (drawable is ITabbableContainer tabbable && tabbable.CanBeTabbedTo)
-                    return drawable;
+                else if (drawable is ITabbableContainer tabbable && tabbable.CanBeTabbedTo && focusManager.ChangeFocus(drawable))
+                    return;
 
                 if (drawable is CompositeDrawable composite)
                 {
@@ -91,8 +92,6 @@ private Drawable nextTabStop(CompositeDrawable target, bool reverse)
                     }
                 }
             }
-
-            return null;
         }
     }
 }