Fix 14062: Exclude sizing grip width from DisplayRectangle when SizingGrip is enabled

src/System.Windows.Forms/PublicAPI.Unshipped.txt

@@ -1,3 +1,4 @@
+override System.Windows.Forms.StatusStrip.DisplayRectangle.get -> System.Drawing.Rectangle
 static System.Windows.Forms.Application.SetColorMode(System.Windows.Forms.SystemColorMode systemColorMode) -> void
 static System.Windows.Forms.TaskDialog.ShowDialogAsync(nint hwndOwner, System.Windows.Forms.TaskDialogPage! page, System.Windows.Forms.TaskDialogStartupLocation startupLocation = System.Windows.Forms.TaskDialogStartupLocation.CenterOwner) -> System.Threading.Tasks.Task<System.Windows.Forms.TaskDialogButton!>!
 static System.Windows.Forms.TaskDialog.ShowDialogAsync(System.Windows.Forms.IWin32Window! owner, System.Windows.Forms.TaskDialogPage! page, System.Windows.Forms.TaskDialogStartupLocation startupLocation = System.Windows.Forms.TaskDialogStartupLocation.CenterOwner) -> System.Threading.Tasks.Task<System.Windows.Forms.TaskDialogButton!>!

src/System.Windows.Forms/System/Windows/Forms/Controls/ToolStrips/StatusStrip.cs

@@ -309,6 +309,39 @@ internal override Size GetPreferredSizeCore(Size proposedSize)
         return base.GetPreferredSizeCore(proposedSize);
     }
 
+    /// <summary>
+    ///  Returns the client rect of the display area of the control.
+    ///  When SizingGrip is enabled, `DisplayRectangle` excludes the sizing grip width.
+    /// </summary>
+    public override Rectangle DisplayRectangle
+    {
+        get
+        {
+            Rectangle rectangle = base.DisplayRectangle;
+
+            if (!SizingGrip)
+            {
+                return rectangle;
+            }
+
+            Rectangle grip = SizeGripBounds;
+            int remainingWidth = rectangle.Width - grip.Width;
+            if (grip.IsEmpty || remainingWidth <= 0)
+            {
+                return rectangle;
+            }
+
+            if (RightToLeft == RightToLeft.Yes)
+            {
+                rectangle.X += grip.Width;
+            }
+
+            rectangle.Width = remainingWidth;
+
+            return rectangle;
+        }
+    }
+
     protected override void OnPaintBackground(PaintEventArgs e)
     {
         base.OnPaintBackground(e);

src/test/unit/System.Windows.Forms/System/Windows/Forms/AccessibleObjects/StatusStrip.StatusStripAccessibleObjectTests.cs

@@ -933,7 +933,7 @@ static ToolStripItem CreateStatusStripItem()
             return new ToolStripStatusLabel()
             {
                 AutoSize = false,
-                Size = new Size(50, 25)
+                Size = new Size(40, 25)
             };
         }
     }

src/test/unit/System.Windows.Forms/System/Windows/Forms/StatusStripTests.cs

@@ -65,7 +65,7 @@ public void StatusStrip_Ctor_Default()
         Assert.False(control.DesignMode);
         Assert.Empty(control.DisplayedItems);
         Assert.Same(control.DisplayedItems, control.DisplayedItems);
-        Assert.Equal(new Rectangle(1, 0, 185, 22), control.DisplayRectangle);
+        Assert.Equal(new Rectangle(1, 0, 173, 22), control.DisplayRectangle);
         Assert.Equal(DockStyle.Bottom, control.Dock);
         Assert.NotNull(control.DockPadding);
         Assert.Same(control.DockPadding, control.DockPadding);
@@ -108,7 +108,7 @@ public void StatusStrip_Ctor_Default()
         Assert.Equal(Point.Empty, control.Location);
         Assert.Equal(Padding.Empty, control.Margin);
         Assert.Equal(Size.Empty, control.MaximumSize);
-        Assert.Equal(new Size(185, 22), control.MaxItemSize);
+        Assert.Equal(new Size(173, 22), control.MaxItemSize);
         Assert.Equal(Size.Empty, control.MinimumSize);
         Assert.Equal(Orientation.Horizontal, control.Orientation);
         Assert.NotNull(control.OverflowButton);