HighlightColor support for overriding colors

Project/Src/Document/HighlightingStrategy/HighlightColor.cs

@@ -108,6 +108,19 @@ namespace ICSharpCode.TextEditor.Document
             }
         }
 
+        /// <summary>
+        ///     Creates a new instance of <see cref="HighlightColor" />
+        /// </summary>
+        public HighlightColor(HighlightColor original, Color color, Color backColor)
+        {
+            Bold = original.Bold;
+            Italic = original.Italic;
+            HasForeground = original.HasForeground;
+            HasBackground = original.HasBackground;
+            Color = color;
+            BackgroundColor = backColor;
+        }
+
         /// <summary>
         ///     Creates a new instance of <see cref="HighlightColor" />
         /// </summary>

Project/Src/Document/HighlightingStrategy/TextWord.cs

@@ -74,7 +74,7 @@ namespace ICSharpCode.TextEditor.Document
             get
             {
                 if (color == null)
-                    return Color.Black;
+                    return SystemColors.WindowText;
                 return color.Color;
             }
         }

Project/Src/Document/LineManager/LineSegment.cs

@@ -72,7 +72,7 @@ namespace ICSharpCode.TextEditor.Document
                 }
             }
 
-            return new HighlightColor(Color.Black, bold: false, italic: false);
+            return new HighlightColor(SystemColors.WindowText, bold: false, italic: false);
         }
 
         /// <summary>

Project/Src/Gui/DrawableLine.cs

@@ -37,7 +37,7 @@ namespace ICSharpCode.TextEditor
                     else
                         words.Add(new SimpleTextWord(TextWordType.Word, word.Word, word.Bold, word.Color));
             else
-                words.Add(new SimpleTextWord(TextWordType.Word, document.GetText(line), Bold: false, Color.Black));
+                words.Add(new SimpleTextWord(TextWordType.Word, document.GetText(line), Bold: false, SystemColors.WindowText));
         }
 
         public int LineLength
@@ -174,8 +174,8 @@ namespace ICSharpCode.TextEditor
 
         private class SimpleTextWord
         {
-            internal static readonly SimpleTextWord Space = new SimpleTextWord(TextWordType.Space, " ", Bold: false, Color.Black);
-            internal static readonly SimpleTextWord Tab = new SimpleTextWord(TextWordType.Tab, "\t", Bold: false, Color.Black);
+            internal static readonly SimpleTextWord Space = new SimpleTextWord(TextWordType.Space, " ", Bold: false, SystemColors.WindowText);
+            internal static readonly SimpleTextWord Tab = new SimpleTextWord(TextWordType.Tab, "\t", Bold: false, SystemColors.WindowText);
             internal readonly Color Color;
             internal readonly TextWordType Type;
             internal bool Bold;

Project/Src/Util/RtfWriter.cs

@@ -57,7 +57,7 @@ namespace ICSharpCode.TextEditor.Util
         {
             var rtf = new StringBuilder();
             var firstLine = true;
-            var curColor = Color.Black;
+            var curColor = SystemColors.WindowText;
             var oldItalic = false;
             var oldBold = false;
             var escapeSequence = false;

Project/Src/Util/TipText.cs

@@ -24,11 +24,11 @@ namespace ICSharpCode.TextEditor.Util
 
         private void DrawTriangle(float x, float y, bool flipped)
         {
-            var brush = BrushRegistry.GetBrush(Color.FromArgb(red: 192, green: 192, blue: 192));
+            var brush = SystemBrushes.Info;
             Graphics.FillRectangle(brush, new RectangleF(x, y, triHeight, triHeight));
             var triHeight2 = triHeight/2;
             var triHeight4 = triHeight/4;
-            brush = Brushes.Black;
+            brush = SystemBrushes.InfoText;
             if (flipped)
                 Graphics.FillPolygon(
                     brush, new[]