fix: dark mode checkboxes in CustomTreeView

- Added ThemeManager.DrawDarkCheckBox to render dark-themed rounded checkboxes
- Fixed TreeView and Proxy checkboxes showing white backgrounds in dark mode due to CheckBoxRenderer drawing opaque system-themed glyphs. > Still need to fix the actual checkmark to match the top checkboxes.
- Disabled DrawDefault for checkbox tree nodes in dark mode and manually draw the row background, text, and checkbox glyphs.
- Checkbox glyph sizing now uses CheckBoxRenderer.GetGlyphSize for proper DPI scaling. (Probably)

CreamInstaller/Components/CustomTreeView.cs

@@ -75,11 +75,14 @@ internal sealed class CustomTreeView : TreeView
 
     private void DrawTreeNode(object sender, DrawTreeNodeEventArgs e)
     {
-        e.DrawDefault = true;
         TreeNode node = e.Node;
         if (node is not { IsVisible: true })
+        {
+            e.DrawDefault = true;
             return;
+        }
 
+        bool dark = Program.DarkModeEnabled;
         bool highlighted = (e.State & TreeNodeStates.Selected) == TreeNodeStates.Selected && Focused;
         Graphics graphics = e.Graphics;
 
@@ -103,12 +106,43 @@ internal sealed class CustomTreeView : TreeView
             }
         }
 
+        Form form = FindForm();
+
+        if (dark && CheckBoxes)
+        {
+            // In dark mode we take full ownership of the row so the system never
+            // gets a chance to paint a light-background checkbox.
+            e.DrawDefault = false;
+
+            // Row background
+            Rectangle rowRect = new(0, node.Bounds.Top, ClientSize.Width, node.Bounds.Height);
+            graphics.FillRectangle(highlighted ? selectionBrush : backBrush, rowRect);
+
+            // Node text
+            Font nodeFont = node.NodeFont ?? Font;
+            Color textColor = Enabled ? ForeColor : SystemColors.GrayText;
+            TextRenderer.DrawText(graphics, node.Text, nodeFont,
+                new Point(node.Bounds.Left, node.Bounds.Top + 1), textColor, TextFormatFlags.Default);
+
+            // Checkbox glyph – pure GDI so it matches the dark-themed CheckBox controls
+            CheckBoxState cbState = node.Checked
+                ? (Enabled ? CheckBoxState.CheckedNormal : CheckBoxState.CheckedDisabled)
+                : (Enabled ? CheckBoxState.UncheckedNormal : CheckBoxState.UncheckedDisabled);
+            Size cbSize = CheckBoxRenderer.GetGlyphSize(graphics, cbState);
+            int cbX = node.Bounds.Left - cbSize.Width - 2;
+            int cbY = node.Bounds.Top + node.Bounds.Height / 2 - cbSize.Height / 2;
+            ThemeManager.DrawDarkCheckBox(graphics, new Point(cbX, cbY), cbSize, node.Checked, Enabled);
+        }
+        else
+        {
+            e.DrawDefault = true;
+        }
+
         Font font = node.NodeFont ?? Font;
         Brush brush = highlighted ? (Brush)selectionBrush : backBrush;
         Rectangle bounds = node.Bounds;
         Rectangle selectionBounds = bounds;
 
-        Form form = FindForm();
         if (form is not SelectForm and not SelectDialogForm)
             return;
 
@@ -168,18 +202,19 @@ internal sealed class CustomTreeView : TreeView
                     graphics.FillRectangle(brush, bounds);
                 }
 
-                CheckBoxState checkBoxState = selection.UseProxy
-                    ? Enabled ? CheckBoxState.CheckedPressed : CheckBoxState.CheckedDisabled
-                    : Enabled
-                        ? CheckBoxState.UncheckedPressed
-                        : CheckBoxState.UncheckedDisabled;
-                size = CheckBoxRenderer.GetGlyphSize(graphics, checkBoxState);
+                CheckBoxState proxyState = selection.UseProxy
+                    ? (Enabled ? CheckBoxState.CheckedNormal : CheckBoxState.CheckedDisabled)
+                    : (Enabled ? CheckBoxState.UncheckedNormal : CheckBoxState.UncheckedDisabled);
+                size = CheckBoxRenderer.GetGlyphSize(graphics, proxyState);
                 bounds = bounds with { X = bounds.X + bounds.Width, Width = size.Width };
                 selectionBounds = new(selectionBounds.Location, selectionBounds.Size + bounds.Size with { Height = 0 });
                 Rectangle checkBoxBounds = bounds;
                 graphics.FillRectangle(backBrush, bounds);
                 point = new(bounds.Left, bounds.Top + bounds.Height / 2 - size.Height / 2 - 1);
-                CheckBoxRenderer.DrawCheckBox(graphics, point, checkBoxState);
+                if (dark)
+                    ThemeManager.DrawDarkCheckBox(graphics, point, size, selection.UseProxy, Enabled);
+                else
+                    CheckBoxRenderer.DrawCheckBox(graphics, point, proxyState);
 
                 text = ProxyToggleString;
                 size = TextRenderer.MeasureText(graphics, text, font);

CreamInstaller/Utility/ThemeManager.cs

@@ -422,6 +422,70 @@ internal static class ThemeManager
     // button is centralized here so theming resides in ThemeManager.
     // -----------------------------------------------------------------
 
+    // Dark checkbox colors – matched to how the system renders the "All" CheckBox control
+    // in dark mode: dark fill, mid-gray border, light foreground tick.
+    private static readonly Color DarkCbBorder = ColorTranslator.FromHtml("#6B6B6B");
+    private static readonly Color DarkCbDisabledBorder = ColorTranslator.FromHtml("#454545");
+
+    /// <summary>
+    /// Draws a checkbox glyph in pure GDI that matches the appearance of a dark-themed
+    /// WinForms CheckBox control (same background, border, tick colors, and rounded corners).
+    /// Use this in owner-draw contexts where CheckBoxRenderer always paints a white background.
+    /// </summary>
+    internal static void DrawDarkCheckBox(Graphics g, Point point, Size glyphSize, bool isChecked, bool enabled = true)
+    {
+        if (g is null) return;
+        int w = glyphSize.Width;
+        int h = glyphSize.Height;
+        Rectangle box = new(point.X, point.Y, w - 1, h - 1);
+        int radius = Math.Max(2, w / 5); // rounded corner radius proportional to glyph size
+
+        // Build rounded rectangle path
+        using System.Drawing.Drawing2D.GraphicsPath path = RoundedRect(box, radius);
+
+        // Fill
+        using SolidBrush fillBrush = new(DarkBackAlt);
+        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
+        g.FillPath(fillBrush, path);
+
+        // Border
+        using Pen borderPen = new(enabled ? DarkCbBorder : DarkCbDisabledBorder);
+        g.DrawPath(borderPen, path);
+
+        if (isChecked)
+        {
+            Color tickColor = enabled ? DarkFore : DarkForeDim;
+            using Pen tickPen = new(tickColor, 1.7f)
+            {
+                StartCap = System.Drawing.Drawing2D.LineCap.Round,
+                EndCap = System.Drawing.Drawing2D.LineCap.Round,
+                LineJoin = System.Drawing.Drawing2D.LineJoin.Round,
+            };
+            // Scale tick proportionally to the glyph size
+            float scaleX = w / 13f;
+            float scaleY = h / 13f;
+            g.DrawLines(tickPen, new PointF[]
+            {
+                new(point.X + 2 * scaleX, point.Y + 6 * scaleY),
+                new(point.X + 5 * scaleX, point.Y + 9 * scaleY),
+                new(point.X + 10 * scaleX, point.Y + 3 * scaleY),
+            });
+        }
+        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.Default;
+    }
+
+    private static System.Drawing.Drawing2D.GraphicsPath RoundedRect(Rectangle r, int radius)
+    {
+        int d = radius * 2;
+        System.Drawing.Drawing2D.GraphicsPath path = new();
+        path.AddArc(r.Left, r.Top, d, d, 180, 90);
+        path.AddArc(r.Right - d, r.Top, d, d, 270, 90);
+        path.AddArc(r.Right - d, r.Bottom - d, d, d, 0, 90);
+        path.AddArc(r.Left, r.Bottom - d, d, d, 90, 90);
+        path.CloseFigure();
+        return path;
+    }
+
     /// <summary>
     /// Draws the themed combobox area (background, border and text) used in CustomTreeView.
     /// This centralizes colors and rendering for light/dark modes.