2 files changed, 10 insertions, 4 deletions
diff --git a/src/application/editor.cpp b/src/application/editor.cpp
index 1cc45f3c7..56984dcbb 100644
--- a/src/application/editor.cpp
+++ b/src/application/editor.cpp
@@ -109,15 +109,19 @@ Editor::getActiveDocument()
 void
 Editor::addDocument (SPDocument *doc)
 {
-    g_assert (!g_slist_find (_instance->_documents, doc));
-    _instance->_documents = g_slist_append (_instance->_documents, doc);
+    if ( _instance->_document_set.find(doc) == _instance->_document_set.end() ) {
+        _instance->_documents = g_slist_append (_instance->_documents, doc);
+    }
+    _instance->_document_set.insert(doc);
 }
 
 void
 Editor::removeDocument (SPDocument *doc)
 {
-    g_assert (g_slist_find (_instance->_documents, doc));
-    _instance->_documents = g_slist_remove (_instance->_documents, doc);
+    _instance->_document_set.erase(doc);
+    if ( _instance->_document_set.find(doc) == _instance->_document_set.end() ) {
+        _instance->_documents = g_slist_remove (_instance->_documents, doc);
+    }
 }
 
 SPDesktop* 
diff --git a/src/application/editor.h b/src/application/editor.h
index 9d2ce493c..a6fe66688 100644
--- a/src/application/editor.h
+++ b/src/application/editor.h
@@ -19,6 +19,7 @@
 #include <sigc++/sigc++.h>
 #include <glib/gslist.h>
 #include <glibmm/ustring.h>
+#include <set>
 #include "app-prototype.h"
 
 class SPDesktop;
@@ -96,6 +97,7 @@ protected:
     Editor(Editor const &);
     Editor& operator=(Editor const &);
 
+    std::multiset<SPDocument *> _document_set;
     GSList         *_documents;
     GSList         *_desktops;
     gchar          *_argv0;