diff --git a/src/dynamic_buffer_iterator.cc b/src/dynamic_buffer_iterator.cc
deleted file mode 100644
index 363207e4b..000000000
--- a/src/dynamic_buffer_iterator.cc
+++ /dev/null
@@ -1,73 +0,0 @@
-#include "dynamic_buffer_iterator.hh"
-
-namespace Kakoune
-{
-
-DynamicBufferIterator::DynamicBufferIterator(const Buffer& buffer,
-                                             BufferPos position)
-    : BufferIterator(buffer, position)
-{
-    register_ifp();
-}
-
-DynamicBufferIterator::DynamicBufferIterator(DynamicBufferIterator&& other)
-    : BufferIterator(other)
-{
-    register_ifp();
-}
-
-DynamicBufferIterator::DynamicBufferIterator(const BufferIterator& other)
-    : BufferIterator(other)
-{
-    register_ifp();
-}
-
-DynamicBufferIterator& DynamicBufferIterator::operator=(const BufferIterator& other)
-{
-    unregister_ifn();
-    BufferIterator::operator=(other);
-    register_ifp();
-
-    return *this;
-}
-
-DynamicBufferIterator::~DynamicBufferIterator()
-{
-    unregister_ifn();
-}
-
-void DynamicBufferIterator::on_modification(const Modification& modification)
-{
-    if (*this < modification.position)
-        return;
-
-    size_t length = modification.content.length();
-    if (modification.type == Modification::Erase)
-    {
-        // do not move length on the other side of the inequality,
-        // as modification.position + length may be after buffer end
-        if (*this - length <= modification.position)
-            BufferIterator::operator=(modification.position);
-        else
-            *this -= length;
-    }
-    else
-    {
-        assert(modification.type == Modification::Insert);
-        *this += length;
-    }
-}
-
-void DynamicBufferIterator::register_ifp()
-{
-    if (is_valid())
-        const_cast<Buffer&>(buffer()).register_modification_listener(this);
-}
-
-void DynamicBufferIterator::unregister_ifn()
-{
-    if (is_valid())
-        const_cast<Buffer&>(buffer()).unregister_modification_listener(this);
-}
-
-}
diff --git a/src/dynamic_buffer_iterator.hh b/src/dynamic_buffer_iterator.hh
deleted file mode 100644
index 873792bd3..000000000
--- a/src/dynamic_buffer_iterator.hh
+++ /dev/null
@@ -1,35 +0,0 @@
-#ifndef dynamic_buffer_iterator_hh_INCLUDED
-#define dynamic_buffer_iterator_hh_INCLUDED
-
-#include "buffer.hh"
-
-namespace Kakoune
-{
-
-class DynamicBufferIterator : public BufferIterator,
-                              public ModificationListener
-{
-public:
-    DynamicBufferIterator() : BufferIterator() {}
-    DynamicBufferIterator(const Buffer& buffer, BufferPos position);
-    DynamicBufferIterator(const BufferIterator& other);
-    DynamicBufferIterator(const DynamicBufferIterator& other)
-        : BufferIterator(other) { register_ifp(); }
-
-    DynamicBufferIterator(DynamicBufferIterator&& other);
-    DynamicBufferIterator& operator=(const BufferIterator& other);
-    DynamicBufferIterator& operator=(const DynamicBufferIterator& other)
-    { return this->operator= (static_cast<const BufferIterator&>(other)); }
-    ~DynamicBufferIterator();
-
-   void on_modification(const Modification& modification);
-
-private:
-   void register_ifp();
-   void unregister_ifn();
-};
-
-
-}
-
-#endif // dynamic_buffer_iterator_hh_INCLUDED
diff --git a/src/window.cc b/src/window.cc
index 4e1e481fa..52edf3315 100644
--- a/src/window.cc
+++ b/src/window.cc
@@ -11,6 +11,55 @@
 namespace Kakoune
 {
 
+Selection::Selection(const BufferIterator& first, const BufferIterator& last,
+                     const CaptureList& captures)
+    : m_first(first), m_last(last), m_captures(captures)
+{
+   register_with_buffer();
+}
+
+Selection::Selection(const BufferIterator& first, const BufferIterator& last,
+                     CaptureList&& captures)
+    : m_first(first), m_last(last), m_captures(captures)
+{
+   register_with_buffer();
+}
+
+Selection::Selection(const Selection& other)
+    : m_first(other.m_first), m_last(other.m_last),
+      m_captures(other.m_captures)
+{
+   register_with_buffer();
+}
+
+Selection::Selection(Selection&& other)
+    : m_first(other.m_first), m_last(other.m_last),
+      m_captures(other.m_captures)
+{
+   register_with_buffer();
+}
+
+Selection::~Selection()
+{
+   unregister_with_buffer();
+}
+
+Selection& Selection::operator=(const Selection& other)
+{
+   const bool new_buffer = &m_first.buffer() != &other.m_first.buffer();
+   if (new_buffer)
+       unregister_with_buffer();
+
+   m_first    = other.m_first;
+   m_last     = other.m_last;
+   m_captures = other.m_captures;
+
+   if (new_buffer)
+       register_with_buffer();
+
+   return *this;
+}
+
 BufferIterator Selection::begin() const
 {
     return std::min(m_first, m_last);
@@ -37,6 +86,45 @@ BufferString Selection::capture(size_t index) const
     return "";
 }
 
+static void update_iterator(const Modification& modification,
+                            BufferIterator& iterator)
+{
+    if (iterator < modification.position)
+        return;
+
+    size_t length = modification.content.length();
+    if (modification.type == Modification::Erase)
+    {
+        // do not move length on the other side of the inequality,
+        // as modification.position + length may be after buffer end
+        if (iterator - length <= modification.position)
+            iterator = modification.position;
+        else
+            iterator -= length;
+    }
+    else
+    {
+        assert(modification.type == Modification::Insert);
+        iterator += length;
+    }
+}
+
+void Selection::on_modification(const Modification& modification)
+{
+    update_iterator(modification, m_first);
+    update_iterator(modification, m_last);
+}
+
+void Selection::register_with_buffer()
+{
+    const_cast<Buffer&>(m_first.buffer()).register_modification_listener(this);
+}
+
+void Selection::unregister_with_buffer()
+{
+    const_cast<Buffer&>(m_first.buffer()).unregister_modification_listener(this);
+}
+
 struct scoped_undo_group
 {
     scoped_undo_group(Buffer& buffer)
diff --git a/src/window.hh b/src/window.hh
index 628730541..e1591d40d 100644
--- a/src/window.hh
+++ b/src/window.hh
@@ -4,7 +4,6 @@
 #include <functional>
 
 #include "buffer.hh"
-#include "dynamic_buffer_iterator.hh"
 #include "display_buffer.hh"
 #include "completion.hh"
 #include "highlighter.hh"
@@ -16,17 +15,22 @@
 namespace Kakoune
 {
 
-struct Selection
+struct Selection : public ModificationListener
 {
     typedef std::vector<BufferString> CaptureList;
 
     Selection(const BufferIterator& first, const BufferIterator& last,
-              const CaptureList& captures = CaptureList())
-        : m_first(first), m_last(last), m_captures(captures) {}
+              const CaptureList& captures = CaptureList());
 
     Selection(const BufferIterator& first, const BufferIterator& last,
-              CaptureList&& captures)
-        : m_first(first), m_last(last), m_captures(captures) {}
+              CaptureList&& captures);
+
+    Selection(const Selection& other);
+    Selection(Selection&& other);
+
+    ~Selection();
+
+    Selection& operator=(const Selection& other);
 
     BufferIterator begin() const;
     BufferIterator end() const;
@@ -40,10 +44,17 @@ struct Selection
     const CaptureList& captures() const { return m_captures; }
 
 private:
-    DynamicBufferIterator m_first;
-    DynamicBufferIterator m_last;
+    BufferIterator m_first;
+    BufferIterator m_last;
 
     CaptureList m_captures;
+
+    void on_modification(const Modification& modification);
+
+    void register_with_buffer();
+    void unregister_with_buffer();
+
+    void check_invariant();
 };
 
 typedef std::vector<Selection> SelectionList;