Fixed bug introduced in last revision.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@4573 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Document/DocumentChangeEventArgs.cs

@@ -50,7 +50,8 @@ namespace ICSharpCode.AvalonEdit.Document
 				OffsetChangeMap map = offsetChangeMap;
 				if (map == null) {
 					// create OffsetChangeMap on demand
-					offsetChangeMap = OffsetChangeMap.FromSingleElement(CreateSingleChangeMapEntry());
+					map = OffsetChangeMap.FromSingleElement(CreateSingleChangeMapEntry());
+					offsetChangeMap = map;
 				}
 				return map;
 			}