Merge pull request #12719 from LeafShi1/BackPort_PR12646_and_12092_to_release9.0

[release/9.0] Get rid of an unexpected white line above the status strip due to a changed renderer

Author: LeafShi1

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

@@ -29,10 +29,7 @@ public StatusStrip()
         SuspendLayout();
         CanOverflow = false;
         LayoutStyle = ToolStripLayoutStyle.Table;
-
-        // Default changed for SystemColorMode from System to ManagerRenderMode.
-        // Also to be consistent to the MenuStrip.
-        RenderMode = ToolStripRenderMode.ManagerRenderMode;
+        RenderMode = ToolStripRenderMode.System;
         GripStyle = ToolStripGripStyle.Hidden;
 
         SetStyle(ControlStyles.ResizeRedraw, true);
@@ -363,6 +360,17 @@ protected override void OnLayout(LayoutEventArgs levent)
         EnsureRightToLeftGrip();
     }
 
+    internal override void ResetRenderMode()
+    {
+        RenderMode = ToolStripRenderMode.System;
+    }
+
+    internal override bool ShouldSerializeRenderMode()
+    {
+        // We should NEVER serialize custom.
+        return (RenderMode is not ToolStripRenderMode.System and not ToolStripRenderMode.Custom);
+    }
+
     internal override bool SupportsUiaProviders => true;
 
     protected override void SetDisplayedItems()

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

@@ -146,8 +146,9 @@ protected override void OnRenderSplitButtonBackground(ToolStripItemRenderEventAr
             else if (item.Selected)
             {
                 g.FillRectangle(SystemBrushes.Highlight, bounds);
+                g.DrawRectangle(SystemPens.HighlightText, dropDownRect);
+
                 DrawHightContrastDashedBorder(g, e.Item);
-                g.DrawRectangle(SystemPens.ButtonHighlight, dropDownRect);
             }
 
             Color arrowColor = item.Selected && !item.Pressed ? SystemColors.HighlightText : SystemColors.ControlText;

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

@@ -575,6 +575,17 @@ protected override void OnRenderSplitButtonBackground(ToolStripItemRenderEventAr
             {
                 DrawArrow(new ToolStripArrowRenderEventArgs(g, splitButton, splitButton.DropDownButtonBounds, arrowColor, ArrowDirection.Down));
             }
+
+            ToolBarState state = GetToolBarState(e.Item);
+            if (e.Item is ToolStripSplitButton item && !SystemInformation.HighContrast &&
+                (state == ToolBarState.Hot || state == ToolBarState.Pressed || state == ToolBarState.Checked))
+            {
+                var clientBounds = item.ClientBounds;
+                bounds.Height -= 1;
+                ControlPaint.DrawBorderSimple(g, clientBounds, SystemColors.Highlight);
+                using var brush = SystemColors.Highlight.GetCachedSolidBrushScope();
+                g.FillRectangle(brush, item.SplitterBounds);
+            }
         }
         else
         {

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

@@ -296,7 +296,10 @@ protected override void OnRenderSplitButtonBackground(ToolStripItemRenderEventAr
 
         if (buttonPressedOrSelected && !item.Pressed)
         {
-            using var brush = ColorTable.ButtonSelectedBorder.GetCachedSolidBrushScope();
+#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+            using var brush = Application.IsDarkModeEnabled ?
+                Color.Silver.GetCachedSolidBrushScope() : ColorTable.ButtonSelectedBorder.GetCachedSolidBrushScope();
+#pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
             g.FillRectangle(brush, item.SplitterBounds);
         }
 

src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/StatusStripTests.cs

@@ -556,18 +556,18 @@ public void StatusStrip_RenderMode_ResetValue_Success()
 
         control.RenderMode = ToolStripRenderMode.System;
         Assert.Equal(ToolStripRenderMode.System, control.RenderMode);
-        Assert.True(property.CanResetValue(control));
+        Assert.False(property.CanResetValue(control));
 
         control.Renderer = new SubToolStripRenderer();
         Assert.Equal(ToolStripRenderMode.Custom, control.RenderMode);
         Assert.False(property.CanResetValue(control));
 
         control.RenderMode = ToolStripRenderMode.ManagerRenderMode;
         Assert.Equal(ToolStripRenderMode.ManagerRenderMode, control.RenderMode);
-        Assert.False(property.CanResetValue(control));
+        Assert.True(property.CanResetValue(control));
 
         property.ResetValue(control);
-        Assert.Equal(ToolStripRenderMode.ManagerRenderMode, control.RenderMode);
+        Assert.Equal(ToolStripRenderMode.System, control.RenderMode);
         Assert.False(property.CanResetValue(control));
     }
 
@@ -584,18 +584,18 @@ public void StatusStrip_RenderMode_ShouldSerializeValue_Success()
 
         control.RenderMode = ToolStripRenderMode.System;
         Assert.Equal(ToolStripRenderMode.System, control.RenderMode);
-        Assert.True(property.ShouldSerializeValue(control));
+        Assert.False(property.ShouldSerializeValue(control));
 
         control.Renderer = new SubToolStripRenderer();
         Assert.Equal(ToolStripRenderMode.Custom, control.RenderMode);
         Assert.False(property.ShouldSerializeValue(control));
 
         control.RenderMode = ToolStripRenderMode.ManagerRenderMode;
         Assert.Equal(ToolStripRenderMode.ManagerRenderMode, control.RenderMode);
-        Assert.False(property.ShouldSerializeValue(control));
+        Assert.True(property.ShouldSerializeValue(control));
 
         property.ResetValue(control);
-        Assert.Equal(ToolStripRenderMode.ManagerRenderMode, control.RenderMode);
+        Assert.Equal(ToolStripRenderMode.System, control.RenderMode);
         Assert.False(property.ShouldSerializeValue(control));
     }
 

src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/ToolStripButtonTests.Rendering.cs

@@ -162,8 +162,9 @@ public void ToolStripButton_SplitButton_Selected_RendersBackgroundCorrectly_High
                 bounds: null,
                 points: null,
                 State.Brush(SystemColors.Highlight, BRUSH_STYLE.BS_SOLID)),
+           Validate.SkipType(ENHANCED_METAFILE_RECORD_TYPE.EMR_POLYGON16),
            Validate.Repeat(Validate.SkipType(ENHANCED_METAFILE_RECORD_TYPE.EMR_POLYPOLYGON16), 2),
-           Validate.Repeat(Validate.SkipType(ENHANCED_METAFILE_RECORD_TYPE.EMR_POLYGON16), 2));
+           Validate.SkipType(ENHANCED_METAFILE_RECORD_TYPE.EMR_POLYGON16));
     }
 
     private class ToolStripSystemHighContrastRenderer : ToolStripSystemRenderer