diff --git a/ChangeLog b/ChangeLog
index e6a1d7a33..6639ffe21 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2012-01-27  Moritz Bunkus  <moritz@bunkus.org>
 
+	* mmg: bug fix: The header editor was sometimes creating two
+	instances of an element if an element was added to the second or
+	one of the later tracks. Fix for bug 711.
+
 	* mkvpropedit, mmg: bug fix: Trying to modify a file located in a
 	path mounted with GVFS SFTP will no longer crash the
 	programs. Instead an error message is output if an error
diff --git a/src/mmg/header_editor/frame.cpp b/src/mmg/header_editor/frame.cpp
index 60482b2b0..51f353c87 100644
--- a/src/mmg/header_editor/frame.cpp
+++ b/src/mmg/header_editor/frame.cpp
@@ -346,6 +346,8 @@ header_editor_frame_c::handle_tracks(kax_analyzer_data_c *data) {
   if (!m_e_tracks)
     return;
 
+  he_track_type_page_c *last_track_page = NULL;
+
   KaxTracks *kax_tracks = static_cast<KaxTracks *>(m_e_tracks.get_object());
   int track_type        = -1;
   size_t i;
@@ -366,7 +368,8 @@ header_editor_frame_c::handle_tracks(kax_analyzer_data_c *data) {
     wxString title;
     track_type = uint64(*k_track_type);
 
-    he_track_type_page_c *page = new he_track_type_page_c(this, track_type, track_number, m_e_tracks);
+    he_track_type_page_c *page = new he_track_type_page_c(this, track_type, track_number, m_e_tracks, *k_track_entry);
+    last_track_page            = page;
     page->init();
 
     he_value_page_c *child_page;
@@ -500,6 +503,9 @@ header_editor_frame_c::handle_tracks(kax_analyzer_data_c *data) {
 
     // m_tc_tree->ExpandAllChildren(page->m_page_id);
   }
+
+  if (NULL != last_track_page)
+    last_track_page->set_is_last_track(true);
 }
 
 void
diff --git a/src/mmg/header_editor/top_level_page.cpp b/src/mmg/header_editor/top_level_page.cpp
index 288aa9ef2..caf214f83 100644
--- a/src/mmg/header_editor/top_level_page.cpp
+++ b/src/mmg/header_editor/top_level_page.cpp
@@ -21,7 +21,6 @@
 
 #include "common/ebml.h"
 #include "common/segmentinfo.h"
-#include "common/segment_tracks.h"
 #include "common/wx.h"
 #include "mmg/header_editor/frame.h"
 #include "mmg/header_editor/top_level_page.h"
@@ -49,8 +48,5 @@ he_top_level_page_c::do_modifications() {
   if (is_id(m_l1_element, KaxInfo))
     fix_mandatory_segmentinfo_elements(m_l1_element.get_object());
 
-  else if (is_id(m_l1_element, KaxTracks))
-    fix_mandatory_segment_tracks_elements(m_l1_element.get_object());
-
   m_l1_element->UpdateSize(true);
 }
diff --git a/src/mmg/header_editor/track_type_page.cpp b/src/mmg/header_editor/track_type_page.cpp
index 86f851dc3..b1a8e0594 100644
--- a/src/mmg/header_editor/track_type_page.cpp
+++ b/src/mmg/header_editor/track_type_page.cpp
@@ -21,16 +21,20 @@
 #include <matroska/KaxTrackEntryData.h>
 
 #include "common/common_pch.h"
+#include "common/segment_tracks.h"
 #include "common/wx.h"
 #include "mmg/header_editor/track_type_page.h"
 
 he_track_type_page_c::he_track_type_page_c(header_editor_frame_c *parent,
                                            int track_type,
                                            unsigned int track_number,
-                                           ebml_element_cptr l1_element)
+                                           ebml_element_cptr l1_element,
+                                           KaxTrackEntry &track_entry)
   : he_top_level_page_c(parent, "" , l1_element)
   , m_track_type(track_type)
   , m_track_number(track_number)
+  , m_track_entry(track_entry)
+  , m_is_last_track(false)
 {
 }
 
@@ -59,3 +63,19 @@ he_track_type_page_c::translate_ui() {
 
   he_top_level_page_c::translate_ui();
 }
+
+void
+he_track_type_page_c::do_modifications() {
+  he_page_base_c::do_modifications();
+
+  if (!m_is_last_track)
+    return;
+
+  fix_mandatory_segment_tracks_elements(m_l1_element.get_object());
+  m_l1_element->UpdateSize(true);
+}
+
+void
+he_track_type_page_c::set_is_last_track(bool is_last_track) {
+  m_is_last_track = is_last_track;
+}
diff --git a/src/mmg/header_editor/track_type_page.h b/src/mmg/header_editor/track_type_page.h
index abddbda5e..cd8ad007d 100644
--- a/src/mmg/header_editor/track_type_page.h
+++ b/src/mmg/header_editor/track_type_page.h
@@ -24,12 +24,17 @@ class he_track_type_page_c: public he_top_level_page_c {
 public:
   int m_track_type;
   unsigned int m_track_number;
+  KaxTrackEntry &m_track_entry;
+  bool m_is_last_track;
 
 public:
-  he_track_type_page_c(header_editor_frame_c *parent, int track_type, unsigned int track_number, ebml_element_cptr l1_element);
+  he_track_type_page_c(header_editor_frame_c *parent, int track_type, unsigned int track_number, ebml_element_cptr l1_element, KaxTrackEntry &track_entry);
   virtual ~he_track_type_page_c();
 
   virtual void translate_ui();
+
+  virtual void set_is_last_track(bool is_last_track);
+  virtual void do_modifications();
 };
 
 #endif // __HE_TRACK_TYPE_PAGE_H