diff --git a/src/AddIns/BackendBindings/XamlBinding/XamlBinding/Extensions.cs b/src/AddIns/BackendBindings/XamlBinding/XamlBinding/Extensions.cs
index 92aed085f3..c6c143bc2d 100644
--- a/src/AddIns/BackendBindings/XamlBinding/XamlBinding/Extensions.cs
+++ b/src/AddIns/BackendBindings/XamlBinding/XamlBinding/Extensions.cs
@@ -362,7 +362,9 @@ namespace ICSharpCode.XamlBinding
 		
 		public static Brush ToBrush(this Color color)
 		{
-			return new SolidColorBrush(color);
+			var b = new SolidColorBrush(color);
+			b.Freeze();
+			return b;
 		}
 	}
 }
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs
index faf2ca022a..e91c7e8c40 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs
@@ -778,12 +778,13 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		
 		TextRunProperties CreateGlobalTextRunProperties()
 		{
-			return new GlobalTextRunProperties {
-				typeface = this.CreateTypeface(),
-				fontRenderingEmSize = FontSize,
-				foregroundBrush = (Brush)GetValue(Control.ForegroundProperty),
-				cultureInfo = CultureInfo.CurrentCulture
-			};
+			var p = new GlobalTextRunProperties();
+			p.typeface = this.CreateTypeface();
+			p.fontRenderingEmSize = FontSize;
+			p.foregroundBrush = (Brush)GetValue(Control.ForegroundProperty);
+			ExtensionMethods.CheckIsFrozen(p.foregroundBrush);
+			p.cultureInfo = CultureInfo.CurrentCulture;
+			return p;
 		}
 		
 		VisualLineTextParagraphProperties CreateParagraphProperties(TextRunProperties defaultTextRunProperties)
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/VisualLineElementTextRunProperties.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/VisualLineElementTextRunProperties.cs
index 00cddc180e..b4011dcf9e 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/VisualLineElementTextRunProperties.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/VisualLineElementTextRunProperties.cs
@@ -6,6 +6,7 @@ using System.Globalization;
 using System.Windows;
 using System.Windows.Media;
 using System.Windows.Media.TextFormatting;
+using ICSharpCode.AvalonEdit.Utils;
 
 namespace ICSharpCode.AvalonEdit.Rendering
 {
@@ -76,6 +77,7 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		/// </summary>
 		public void SetBackgroundBrush(Brush value)
 		{
+			ExtensionMethods.CheckIsFrozen(value);
 			backgroundBrush = value;
 		}
 		
@@ -143,6 +145,7 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		/// </summary>
 		public void SetForegroundBrush(Brush value)
 		{
+			ExtensionMethods.CheckIsFrozen(value);
 			foregroundBrush = value;
 		}
 		
@@ -177,6 +180,7 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		/// </summary>
 		public void SetTextDecorations(TextDecorationCollection value)
 		{
+			ExtensionMethods.CheckIsFrozen(value);
 			textDecorations = value;
 		}
 		
@@ -196,6 +200,7 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		/// </summary>
 		public void SetTextEffects(TextEffectCollection value)
 		{
+			ExtensionMethods.CheckIsFrozen(value);
 			textEffects = value;
 		}
 	}
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Utils/ExtensionMethods.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Utils/ExtensionMethods.cs
index bb017262b4..2dec831363 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Utils/ExtensionMethods.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Utils/ExtensionMethods.cs
@@ -3,14 +3,12 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Media;
-using System.Windows.Threading;
 using System.Xml;
 
-using ICSharpCode.AvalonEdit.Document;
-
 namespace ICSharpCode.AvalonEdit.Utils
 {
 	static class ExtensionMethods
@@ -187,5 +185,12 @@ namespace ICSharpCode.AvalonEdit.Utils
 			return new Rect(rect.Location.ToWpf(), rect.Size.ToWpf());
 		}
 		#endregion
+		
+		[Conditional("DEBUG")]
+		public static void CheckIsFrozen(Freezable f)
+		{
+			if (f != null && !f.IsFrozen)
+				Debug.WriteLine("Performance warning: Not frozen: " + f.ToString());
+		}
 	}
 }