diff --git a/taglib/toolkit/tlist.h b/taglib/toolkit/tlist.h
index 6171ffdb..406204f4 100644
--- a/taglib/toolkit/tlist.h
+++ b/taglib/toolkit/tlist.h
@@ -121,6 +121,10 @@ namespace TagLib {
 
     /*!
      * Inserts a copy of \a item before \a it.
+     *
+     * \note This method cannot detach because \a it is tied to the internal
+     * list.  Do not make an implicitly shared copy of this list between
+     * getting the iterator and calling this method!
      */
     Iterator insert(Iterator it, const T &item);
 
@@ -199,6 +203,10 @@ namespace TagLib {
 
     /*!
      * Erase the item at \a it from the list.
+     *
+     * \note This method cannot detach because \a it is tied to the internal
+     * list.  Do not make an implicitly shared copy of this list between
+     * getting the iterator and calling this method!
      */
     Iterator erase(Iterator it);
 
@@ -232,6 +240,11 @@ namespace TagLib {
      */
     void setAutoDelete(bool autoDelete);
 
+    /*!
+     * Returns true is auto-deletion is enabled.
+     */
+    bool autoDelete() const;
+
     /*!
      * Returns a reference to item \a i in the list.
      *
@@ -293,7 +306,7 @@ namespace TagLib {
     /*
      * If this List is being shared via implicit sharing, do a deep copy of the
      * data and separate from the shared members.  This should be called by all
-     * non-const subclass members.
+     * non-const subclass members without Iterator parameters.
      */
     void detach();
 
diff --git a/taglib/toolkit/tlist.tcc b/taglib/toolkit/tlist.tcc
index 97da8267..535fb2e7 100644
--- a/taglib/toolkit/tlist.tcc
+++ b/taglib/toolkit/tlist.tcc
@@ -148,7 +148,6 @@ typename List<T>::ConstIterator List<T>::cend() const
 template <class T>
 typename List<T>::Iterator List<T>::insert(Iterator it, const T &item)
 {
-  detach();
   return d->list.insert(it, item);
 }
 
@@ -270,9 +269,16 @@ const T &List<T>::back() const
 template <class T>
 void List<T>::setAutoDelete(bool autoDelete)
 {
+  detach();
   d->autoDelete = autoDelete;
 }
 
+template <class T>
+bool List<T>::autoDelete() const
+{
+  return d->autoDelete;
+}
+
 template <class T>
 T &List<T>::back()
 {
diff --git a/taglib/toolkit/tmap.h b/taglib/toolkit/tmap.h
index eb515d4a..709235eb 100644
--- a/taglib/toolkit/tmap.h
+++ b/taglib/toolkit/tmap.h
@@ -164,12 +164,16 @@ namespace TagLib {
     bool contains(const Key &key) const;
 
     /*!
-     * Erase the item at \a it from the list.
+     * Erase the item at \a it from the map.
+     *
+     * \note This method cannot detach because \a it is tied to the internal
+     * map.  Do not make an implicitly shared copy of this map between
+     * getting the iterator and calling this method!
      */
     Map<Key, T> &erase(Iterator it);
 
     /*!
-     * Erase the item with \a key from the list.
+     * Erase the item with \a key from the map.
      */
     Map<Key, T> &erase(const Key &key);
 
@@ -225,9 +229,9 @@ namespace TagLib {
 
   protected:
     /*
-     * If this List is being shared via implicit sharing, do a deep copy of the
+     * If this Map is being shared via implicit sharing, do a deep copy of the
      * data and separate from the shared members.  This should be called by all
-     * non-const subclass members.
+     * non-const subclass members without Iterator parameters.
      */
     void detach();
 
diff --git a/taglib/toolkit/tmap.tcc b/taglib/toolkit/tmap.tcc
index 067491db..a040b6ce 100644
--- a/taglib/toolkit/tmap.tcc
+++ b/taglib/toolkit/tmap.tcc
@@ -148,7 +148,6 @@ 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;
 }
diff --git a/tests/test_list.cpp b/tests/test_list.cpp
index 6d954e97..776e4bf7 100644
--- a/tests/test_list.cpp
+++ b/tests/test_list.cpp
@@ -60,17 +60,36 @@ public:
 
   void testDetach()
   {
-    List<int> l1;
-    l1.append(1);
-    l1.append(2);
-    l1.append(3);
-    l1.append(4);
+    {
+      List<int> l1;
+      l1.append(1);
+      l1.append(2);
+      l1.append(3);
+      l1.append(4);
 
-    List<int> l2 = l1;
-    auto it = l2.find(3);
-    *it = 33;
-    CPPUNIT_ASSERT_EQUAL(3,  l1[2]);
-    CPPUNIT_ASSERT_EQUAL(33, l2[2]);
+      List<int> l2 = l1;
+      auto it = l2.find(3);
+      *it = 33;
+      CPPUNIT_ASSERT_EQUAL(3,  l1[2]);
+      CPPUNIT_ASSERT_EQUAL(33, l2[2]);
+    }
+    {
+      List<int *> l1;
+      List<int *> l2 = l1;
+      CPPUNIT_ASSERT(!l1.autoDelete());
+      CPPUNIT_ASSERT(!l2.autoDelete());
+      l2.setAutoDelete(true);
+      CPPUNIT_ASSERT(!l1.autoDelete());
+      CPPUNIT_ASSERT(l2.autoDelete());
+    }
+    {
+      List<int> l1;
+      List<int> l2 = l1;
+      l1.insert(l1.begin(), 1);
+      CPPUNIT_ASSERT(!l1.isEmpty());
+      CPPUNIT_ASSERT_EQUAL(1, l1.front());
+      CPPUNIT_ASSERT(l2.isEmpty());
+    }
   }
 
   void bracedInit()