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

@@ -379,6 +379,7 @@ protected override void SetDisplayedItems()
             Rectangle lastItemBounds = Rectangle.Empty;
 
             ToolStripItem? lastItem = null;
+            const double HideIntersectionRatioThreshold = 0.5;
             for (int i = 0; i < Items.Count; i++)
             {
                 ToolStripItem item = Items[i];
@@ -387,9 +388,36 @@ protected override void SetDisplayedItems()
                 // visible.
                 if (overflow || ((IArrangedElement)item).ParticipatesInLayout)
                 {
-                    if (overflow || (SizingGrip && item.Bounds.IntersectsWith(SizeGripBounds)))
+                    bool hide = false;
+
+                    // Check for collisions with SizingGrip when SizingGrip is enabled.
+                    if (!SizeGripBounds.IsEmpty)
+                    {
+                        Rectangle itemBounds = item.Bounds;
+
+                        if (itemBounds.IntersectsWith(SizeGripBounds))
+                        {
+                            Rectangle intersect = Rectangle.Intersect(itemBounds, SizeGripBounds);
+                            double itemArea = Math.Max(1, itemBounds.Width * itemBounds.Height);
+                            double intersectArea = Math.Max(0, intersect.Width * intersect.Height);
+                            double ratio = intersectArea / itemArea;
+
+                            // Only hide intersections when the intersection ratio exceeds a threshold,
+                            // otherwise, slight overlap is allowed.
+                            if (ratio >= HideIntersectionRatioThreshold)
+                            {
+                                hide = true;
+                            }
+                        }
+                    }
+
+                    if (overflow)
+                    {
+                        hide = true;
+                    }
+
+                    if (hide)
                     {
-                        // if the item collides with the size grip, set the location to nomansland.
                         SetItemLocation(item, noMansLand);
                         item.SetPlacement(ToolStripItemPlacement.None);
                     }

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);