diff -r df3820d7989d -r 5b37a10234bc lemon/bits/alteration_notifier.h
--- a/lemon/bits/alteration_notifier.h	Wed Sep 14 10:00:43 2005 +0000
+++ b/lemon/bits/alteration_notifier.h	Fri Sep 16 09:00:18 2005 +0000
@@ -80,6 +80,12 @@
       /// 
       ObserverBase() : registry(0) {}
 
+      ObserverBase(const ObserverBase& copy) {
+	if (copy.attached()) {
+	  copy.getRegistry()->attach(*this);
+	}
+      }
+	
       virtual ~ObserverBase() {}
 
       /// \brief Attaches the observer into an AlterationNotifier.
@@ -111,10 +117,9 @@
       
       /// Gives back true when the observer is attached into a registry.
       bool attached() const { return registry != 0; }
-	
+
     private:
 
-      ObserverBase(const ObserverBase& copy);
       ObserverBase& operator=(const ObserverBase& copy);
 
     protected: