Fix Issue 14167: [HDPI] Cursor editor some items are not displayed in propertyGrid with special DPI settings

src/System.Windows.Forms.Design/src/System/Drawing/Design/CursorEditor.CursorUI.cs

@@ -41,7 +41,7 @@ public CursorUI()
                 }
             }
 
-            _cursorWidth = GetCursorWidthForDpi(Cursors.Default, DeviceDpi);
+            RecalculateCursorWidth(DeviceDpi);
         }
 
         public object? Value { get; private set; }
@@ -50,7 +50,17 @@ public void End()
         {
             _editorService = null;
             Value = null;
-            _cursorWidthCache.Clear();
+            ClearCursorCaches();
+        }
+
+        protected override void OnVisibleChanged(EventArgs e)
+        {
+            base.OnVisibleChanged(e);
+
+            if (Visible && IsHandleCreated)
+            {
+                BeginInvoke((MethodInvoker)ForceRedrawVisibleItems);
+            }
         }
 
         protected override void OnClick(EventArgs e)
@@ -75,7 +85,17 @@ protected override void OnDrawItem(DrawItemEventArgs e)
                 e.Graphics.FillRectangle(SystemBrushes.Control, new Rectangle(e.Bounds.X + 2, e.Bounds.Y + 2, _cursorWidth, e.Bounds.Height - 4));
                 e.Graphics.DrawRectangle(SystemPens.WindowText, new Rectangle(e.Bounds.X + 2, e.Bounds.Y + 2, _cursorWidth - 1, e.Bounds.Height - 4 - 1));
 
-                cursor.DrawStretched(e.Graphics, new Rectangle(e.Bounds.X + 2, e.Bounds.Y + 2, _cursorWidth, e.Bounds.Height - 4));
+                using (DeviceContextHdcScope dc = new(e, applyGraphicsState: false))
+                {
+                    PInvokeCore.DrawIconEx(
+                        (HDC)dc,
+                        e.Bounds.X + 2,
+                        e.Bounds.Y + 2,
+                        cursor,
+                        _cursorWidth,
+                        e.Bounds.Height - 4);
+                }
+
                 e.Graphics.DrawString(text, font, brushText, e.Bounds.X + _cursorWidth + 4, e.Bounds.Y + (e.Bounds.Height - font.Height) / 2);
             }
         }
@@ -113,6 +133,9 @@ public void Start(IWindowsFormsEditorService editorService, object? value)
             _editorService = editorService;
             Value = value;
 
+            // Rebuild width/cache for every drop-down session so owner-draw rows are ready on first paint.
+            RecalculateCursorWidth(DeviceDpi);
+
             // Select the current cursor
             if (value is not null)
             {
@@ -125,14 +148,46 @@ public void Start(IWindowsFormsEditorService editorService, object? value)
                     }
                 }
             }
+
+            Invalidate();
+            Update();
+        }
+
+        private void ForceRedrawVisibleItems()
+        {
+            if (!IsDisposed && IsHandleCreated && Visible)
+            {
+                Invalidate();
+                Update();
+            }
+        }
+
+        private void ClearCursorCaches()
+        {
+            _cursorWidthCache.Clear();
+        }
+
+        private void RecalculateCursorWidth(int dpi)
+        {
+            int cursorWidth = GetCursorWidthForDpi(Cursors.Default, dpi);
+
+            foreach (object item in Items)
+            {
+                if (item is Cursor cursor)
+                {
+                    cursorWidth = Math.Max(cursorWidth, GetCursorWidthForDpi(cursor, dpi));
+                }
+            }
+
+            _cursorWidth = cursorWidth;
         }
 
         protected override void RescaleConstantsForDpi(int deviceDpiOld, int deviceDpiNew)
         {
             base.RescaleConstantsForDpi(deviceDpiOld, deviceDpiNew);
 
-            // Recalculate the representative width using the new DPI; all rows continue to share it to avoid the layout issues seen in #14167.
-            _cursorWidth = GetCursorWidthForDpi(Cursors.Default, deviceDpiNew);
+            // Recalculate the shared column width using the new DPI and the widest standard cursor.
+            RecalculateCursorWidth(deviceDpiNew);
             Invalidate();
         }
     }

src/System.Windows.Forms.Design/tests/UnitTests/System/Drawing/Design/CursorEditorTests.cs

@@ -4,6 +4,8 @@
 #nullable disable
 
 using System.ComponentModel;
+using System.Collections;
+using System.Reflection;
 using System.Windows.Forms.Design;
 using System.Windows.Forms.TestUtilities;
 using Moq;
@@ -74,4 +76,75 @@ public void CursorEditor_GetPaintValueSupported_Invoke_ReturnsFalse(ITypeDescrip
         CursorEditor editor = new();
         Assert.False(editor.GetPaintValueSupported(context));
     }
+
+    [WinFormsFact]
+    public void CursorEditor_CursorUI_CursorWidth_UsesWidestStandardCursor()
+    {
+        Type type = typeof(CursorEditor).GetNestedType("CursorUI", BindingFlags.NonPublic | BindingFlags.Instance)!;
+        using ListBox cursorUI = (ListBox)Activator.CreateInstance(type)!;
+        int dpi = cursorUI.DeviceDpi;
+
+        MethodInfo getCursorWidthForDpiMethod = type.GetMethod("GetCursorWidthForDpi", BindingFlags.NonPublic | BindingFlags.Instance)!;
+        FieldInfo cursorWidthField = type.GetField("_cursorWidth", BindingFlags.NonPublic | BindingFlags.Instance)!;
+
+        int expectedWidth = 0;
+        foreach (object item in cursorUI.Items)
+        {
+            if (item is Cursor cursor)
+            {
+                int width = (int)getCursorWidthForDpiMethod.Invoke(cursorUI, [cursor, dpi])!;
+                expectedWidth = Math.Max(expectedWidth, width);
+            }
+        }
+
+        Assert.NotEqual(0, expectedWidth);
+        Assert.Equal(expectedWidth, (int)cursorWidthField.GetValue(cursorUI)!);
+    }
+
+    [WinFormsFact]
+    public void CursorEditor_CursorUI_Start_RebuildsCursorWidthCache()
+    {
+        Type type = typeof(CursorEditor).GetNestedType("CursorUI", BindingFlags.NonPublic | BindingFlags.Instance)!;
+        using ListBox cursorUI = (ListBox)Activator.CreateInstance(type)!;
+
+        FieldInfo cursorWidthCacheField = type.GetField("_cursorWidthCache", BindingFlags.NonPublic | BindingFlags.Instance)!;
+        MethodInfo endMethod = type.GetMethod("End", BindingFlags.Public | BindingFlags.Instance)!;
+        MethodInfo startMethod = type.GetMethod("Start", BindingFlags.Public | BindingFlags.Instance)!;
+
+        IDictionary cache = (IDictionary)cursorWidthCacheField.GetValue(cursorUI)!;
+        Assert.NotEmpty(cache);
+
+        endMethod.Invoke(cursorUI, null);
+        Assert.Empty(cache);
+
+        Mock<IWindowsFormsEditorService> mockEditorService = new(MockBehavior.Strict);
+        startMethod.Invoke(cursorUI, [mockEditorService.Object, Cursors.Default]);
+        Assert.NotEmpty(cache);
+    }
+
+    [WinFormsFact]
+    public void CursorEditor_CursorUI_OnDrawItem_RestoresGraphicsClip()
+    {
+        Type type = typeof(CursorEditor).GetNestedType("CursorUI", BindingFlags.NonPublic | BindingFlags.Instance)!;
+        using ListBox cursorUI = (ListBox)Activator.CreateInstance(type)!;
+        MethodInfo onDrawItemMethod = type.GetMethod("OnDrawItem", BindingFlags.NonPublic | BindingFlags.Instance)!;
+
+        using Bitmap image = new(600, 400);
+        using Graphics graphics = Graphics.FromImage(image);
+        graphics.SetClip(new Rectangle(10, 10, 580, 380));
+        Rectangle initialClipBounds = Rectangle.Round(graphics.ClipBounds);
+
+        using DrawItemEventArgs args = new(
+            graphics,
+            SystemFonts.DefaultFont,
+            new Rectangle(0, 0, 500, cursorUI.ItemHeight),
+            index: 0,
+            DrawItemState.Default,
+            SystemColors.WindowText,
+            SystemColors.Window);
+
+        onDrawItemMethod.Invoke(cursorUI, [args]);
+
+        Assert.Equal(initialClipBounds, Rectangle.Round(graphics.ClipBounds));
+    }
 }