diff --git a/toolkit/tmap.tcc b/toolkit/tmap.tcc
index b9787a0f..afb7db4c 100644
--- a/toolkit/tmap.tcc
+++ b/toolkit/tmap.tcc
@@ -106,6 +106,7 @@ bool Map<Key, T>::isEmpty() const
 template <class Key, class T>
 typename Map<Key, T>::Iterator Map<Key, T>::find(const Key &key)
 {
+  detach();
   return d->map.find(key);
 }
 
@@ -124,6 +125,7 @@ bool Map<Key, T>::contains(const Key &key) const
 template <class Key, class T>
 Map<Key, T> &Map<Key,T>::erase(Iterator it)
 {
+  detach();
   d->map.erase(it);
   return *this;
 }
@@ -143,7 +145,8 @@ const T &Map<Key, T>::operator[](const Key &key) const
 template <class Key, class T>
 T &Map<Key, T>::operator[](const Key &key)
 {
-    return d->map[key];
+  detach();  
+  return d->map[key];
 }
 
 template <class Key, class T>