fix unit tests

src/AddIns/BackendBindings/XamlBinding/XamlBinding/MarkupExtensionInfo.cs

@@ -32,6 +32,7 @@ namespace ICSharpCode.XamlBinding
 		
 		public int StartOffset { get; set; }
 		public int EndOffset { get; set; }
+		public bool IsClosed { get; set; }
 		
 		public MarkupExtensionInfo()
 			: this(string.Empty, new List<AttributeValue>(), new Dictionary<string, AttributeValue>(StringComparer.OrdinalIgnoreCase))
@@ -163,6 +164,10 @@ namespace ICSharpCode.XamlBinding
 			}
 		}
 		
+		public bool IsClosed {
+			get { return IsString || extensionValue.IsClosed; }
+		}
+		
 		public bool IsString {
 			get { return stringValue != null; }
 		}

src/AddIns/BackendBindings/XamlBinding/XamlBinding/MarkupExtensionParser.cs

@@ -45,6 +45,7 @@ namespace ICSharpCode.XamlBinding
 							break;
 						case MarkupExtensionTokenKind.CloseBrace:
 							info.EndOffset = token.EndOffset + offset;
+							info.IsClosed = true;
 							break;
 						case MarkupExtensionTokenKind.TypeName:
 							info.ExtensionType = token.Value;

src/AddIns/BackendBindings/XamlBinding/XamlBinding/Utils.cs

@@ -126,12 +126,18 @@ namespace ICSharpCode.XamlBinding
 			MarkupExtensionInfo tmp = info;
 			
 			foreach (var item in info.PositionalArguments) {
-				if (item.StartOffset < offset && offset <= item.EndOffset)
+				int endOffset = item.EndOffset;
+				if (!item.IsClosed)
+					endOffset++;
+				if (item.StartOffset < offset && offset < endOffset)
 					tmp = item.IsString ? tmp : GetMarkupExtensionAtPosition(item.ExtensionValue, offset);
 			}
 			
 			foreach (var pair in info.NamedArguments) {
-				if (pair.Value.StartOffset < offset && offset < pair.Value.EndOffset)
+				int endOffset = pair.Value.EndOffset;
+				if (!pair.Value.IsClosed)
+					endOffset++;
+				if (pair.Value.StartOffset < offset && offset < endOffset)
 					tmp = pair.Value.IsString ? tmp : GetMarkupExtensionAtPosition(pair.Value.ExtensionValue, offset);
 			}