diff --git a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedContentNodes.cs b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedContentNodes.cs
index a3c56a8eb4..6c0fa58d24 100644
--- a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedContentNodes.cs
+++ b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedContentNodes.cs
@@ -9,15 +9,13 @@ using System.Linq;
 namespace Debugger.AddIn.Visualizers.Graph
 {
 	/// <summary>
-	/// Remembers which content nodes the user has expanded in the <see cref="PositionedGraph">.
+	/// Holds the expand state of the trees inside nodes of <see cref="PositionedGraph">.
 	/// </summary>
 	public class ExpandedContentNodes
 	{
 		private ExpandedPaths expanded = new ExpandedPaths();
 		
-		public ExpandedContentNodes()
-		{
-		}
+		public ExpandedContentNodes() {}
 		
 		public bool IsExpanded(ContentNode contentNode)
 		{
diff --git a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedExpressions.cs b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedExpressions.cs
index 45d0fe49b7..938bca27fb 100644
--- a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedExpressions.cs
+++ b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedExpressions.cs
@@ -11,7 +11,7 @@ using ICSharpCode.NRefactory.Ast;
 namespace Debugger.AddIn.Visualizers.Graph
 {
 	/// <summary>
-	/// Remembers which properties the user has expanded in the <see cref="PositionedGraph">.
+	/// Holds the expand state of fields and properties in <see cref="PositionedGraph">.
 	/// </summary>
 	public class ExpandedExpressions
 	{
@@ -21,19 +21,19 @@ namespace Debugger.AddIn.Visualizers.Graph
 		{
 		}
 		
-		public bool IsExpanded(Expression expression)
+		public bool IsExpanded(String expression)
 		{
-			return expanded.IsExpanded(expression.PrettyPrint());
+			return expanded.IsExpanded(expression);
 		}
 		
-		public void SetExpanded(Expression expression)
+		public void SetExpanded(String expression)
 		{
-			expanded.SetExpanded(expression.PrettyPrint());
+			expanded.SetExpanded(expression);
 		}
 		
-		public void SetCollapsed(Expression expression)
+		public void SetCollapsed(String expression)
 		{
-			expanded.SetCollapsed(expression.PrettyPrint());
+			expanded.SetCollapsed(expression);
 		}
 	}
 }
diff --git a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedPaths.cs b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedPaths.cs
index 702028f218..58f236143a 100644
--- a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedPaths.cs
+++ b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ExpandedPaths/ExpandedPaths.cs
@@ -13,9 +13,7 @@ namespace Debugger.AddIn.Visualizers.Graph
 	{
 		private Dictionary<string, bool> expandedPaths = new Dictionary<string, bool>();
 		
-		public ExpandedPaths()
-		{
-		}
+		public ExpandedPaths() {}
 		
 		public bool IsExpanded(string path)
 		{
diff --git a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/GraphExpression.cs b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/GraphExpression.cs
index f892f18949..c5959343ac 100644
--- a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/GraphExpression.cs
+++ b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/GraphExpression.cs
@@ -14,12 +14,12 @@ namespace Debugger.AddIn.Visualizers.Graph
 	/// </summary>
 	public class GraphExpression
 	{
-		public Expression Expr { get; set; }
+		public String Expr { get; set; }
 		public Func<Value> GetValue { get; set; }
 		
-		public GraphExpression(Expression expr, Func<Value> getValue)
+		public GraphExpression(String expr, Func<Value> getValue)
 		{
-			if (expr == null) throw new ArgumentNullException("expr");
+			if (String.IsNullOrEmpty(expr)) throw new ArgumentNullException("expr");
 			if (getValue == null) throw new ArgumentNullException("getValue");
 			this.Expr = expr;
 			this.GetValue = getValue;
diff --git a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Layout/PositionedGraph.cs b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Layout/PositionedGraph.cs
index 2052d90ad9..a61482eb50 100644
--- a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Layout/PositionedGraph.cs
+++ b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Layout/PositionedGraph.cs
@@ -19,8 +19,7 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 		
 		public System.Windows.Rect BoundingRect
 		{
-			get
-			{
+			get {
 				double minX = nodes.Select(node => node.Left).Min();
 				double maxX = nodes.Select(node => node.Left + node.Width).Max();
 				double minY = nodes.Select(node => node.Top).Min();
@@ -48,12 +47,9 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 		/// </summary>
 		public IEnumerable<PositionedEdge> Edges
 		{
-			get
-			{
-				foreach	(PositionedNode node in this.Nodes)
-				{
-					foreach (PositionedEdge edge in node.Edges)
-					{
+			get {
+				foreach	(PositionedNode node in this.Nodes) {
+					foreach (PositionedEdge edge in node.Edges) {
 						yield return edge;
 					}
 				}
diff --git a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Layout/TreeModel/ContentNode.cs b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Layout/TreeModel/ContentNode.cs
index 90fcfcf004..d465a5fa5b 100644
--- a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Layout/TreeModel/ContentNode.cs
+++ b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/Layout/TreeModel/ContentNode.cs
@@ -36,7 +36,7 @@ namespace Debugger.AddIn.Visualizers.Graph.Layout
 		/// </summary>
 		public string FullPath
 		{
-			get { return this.containingNode.ObjectNode.Expression.Expr.PrettyPrint() + "/" + this.Path; }
+			get { return this.containingNode.ObjectNode.Expression.Expr + "/" + this.Path; }
 		}
 		
 		private ContentNode parent;
diff --git a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ObjectGraph/ObjectGraphBuilder.cs b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ObjectGraph/ObjectGraphBuilder.cs
index 665ca9e541..5b1f62f881 100644
--- a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ObjectGraph/ObjectGraphBuilder.cs
+++ b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ObjectGraph/ObjectGraphBuilder.cs
@@ -226,8 +226,7 @@ namespace Debugger.AddIn.Visualizers.Graph
 					continue;
 				}
 
-				// ObjectGraphProperty needs an expression
-				// to know whether it is expanded, and to evaluate
+				// ObjectGraphProperty needs string representation to know whether it is expanded
 				var propExpression = new GraphExpression(
 					expression.Expr.AppendMemberReference((IDebugMemberInfo)memberProp),
 					() => expression.GetValue().GetMemberValue(WindowsDebugger.EvalThread, memberProp)
diff --git a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ObjectGraphControl.xaml.cs b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ObjectGraphControl.xaml.cs
index 33ffe9d9b0..67e8241dd2 100644
--- a/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ObjectGraphControl.xaml.cs
+++ b/src/AddIns/Debugger/Debugger.AddIn/Visualizers/Graph/ObjectGraphControl.xaml.cs
@@ -107,8 +107,8 @@ namespace Debugger.AddIn.Visualizers.Graph
 					RefreshView();
 					return;
 				}
-				if (shownExpression == null || value.Expr.PrettyPrint() != shownExpression.Expr.PrettyPrint()) {
-					txtExpression.Text = value.Expr.PrettyPrint();
+				if (shownExpression == null || value.Expr != shownExpression.Expr) {
+					txtExpression.Text = value.Expr;
 					RefreshView();
 				}
 			}