diff --git a/src/plugins/coreplugin/editormanager/editormanager.cpp b/src/plugins/coreplugin/editormanager/editormanager.cpp
index 8893fe74831..65b38d7bc2d 100644
--- a/src/plugins/coreplugin/editormanager/editormanager.cpp
+++ b/src/plugins/coreplugin/editormanager/editormanager.cpp
@@ -507,9 +507,9 @@ EditorToolBar *EditorManager::createToolBar(QWidget *parent)
 
 void EditorManager::removeEditor(IEditor *editor)
 {
-    bool isDuplicate = d->m_editorModel->isDuplicate(editor);
-    d->m_editorModel->removeEditor(editor);
-    if (!isDuplicate)
+    bool lastOneForDocument = false;
+    d->m_editorModel->removeEditor(editor, &lastOneForDocument);
+    if (lastOneForDocument)
         DocumentManager::removeDocument(editor->document());
     ICore::removeContextObject(editor);
 }
@@ -660,21 +660,17 @@ void EditorManager::emptyView(Core::Internal::EditorView *view)
 
     QList<IEditor *> editors = view->editors();
     foreach (IEditor *editor, editors) {
-        if (!d->m_editorModel->isDuplicate(editor)) {
-            QList<IEditor *> duplicates = d->m_editorModel->duplicatesFor(editor);
-            if (!duplicates.isEmpty()) {
-                d->m_editorModel->makeOriginal(duplicates.first());
-            } else {
-                // it's the only editor for that file and it's not a duplicate,
-                // so we need to keep it around (--> in the editor model)
-                if (currentEditor() == editor) {
-                    // we don't want a current editor that is not open in a view
-                    setCurrentEditor(0);
-                }
-                editors.removeAll(editor);
-                view->removeEditor(editor);
-                continue; // don't close the editor
+        if (d->m_editorModel->editorsForDocument(editor->document()).size() == 1) {
+            // it's the only editor for that file
+            // so we need to keep it around (--> in the editor model)
+            if (currentEditor() == editor) {
+                // we don't want a current editor that is not open in a view
+                setCurrentView(view);
+                setCurrentEditor(0);
             }
+            editors.removeAll(editor);
+            view->removeEditor(editor);
+            continue; // don't close the editor
         }
         emit editorAboutToClose(editor);
         removeEditor(editor);
@@ -743,33 +739,6 @@ void EditorManager::closeView(Core::Internal::EditorView *view)
     }
 }
 
-QList<IEditor*>
-    EditorManager::editorsForDocuments(QList<IDocument*> documents) const
-{
-    const QList<IEditor *> editors = openedEditors();
-    QSet<IEditor *> found;
-    foreach (IDocument *document, documents) {
-        foreach (IEditor *editor, editors) {
-            if (editor->document() == document && !found.contains(editor))
-                    found << editor;
-        }
-    }
-    return found.toList();
-}
-
-QList<IDocument *> EditorManager::documentsForEditors(QList<IEditor *> editors) const
-{
-    QSet<IEditor *> handledEditors;
-    QList<IDocument *> documents;
-    foreach (IEditor *editor, editors) {
-        if (!handledEditors.contains(editor)) {
-            documents << editor->document();
-            handledEditors.insert(editor);
-        }
-    }
-    return documents;
-}
-
 bool EditorManager::closeAllEditors(bool askAboutModifiedEditors)
 {
     d->m_editorModel->removeAllRestoredEditors();
@@ -780,19 +749,21 @@ bool EditorManager::closeAllEditors(bool askAboutModifiedEditors)
     return false;
 }
 
-void EditorManager::closeOtherEditors(IEditor *editor)
+void EditorManager::closeOtherEditors(IDocument *document)
 {
     d->m_editorModel->removeAllRestoredEditors();
-    QList<IEditor*> editors = openedEditors();
-    editors.removeAll(editor);
-    closeEditors(editors, true);
+    QList<IEditor *> editorsToClose;
+    foreach (IEditor *editor, openedEditors())
+        if (editor->document() != document)
+            editorsToClose << editor;
+    closeEditors(editorsToClose, true);
 }
 
 void EditorManager::closeOtherEditors()
 {
     IEditor *current = currentEditor();
     QTC_ASSERT(current, return);
-    closeOtherEditors(current);
+    closeOtherEditors(current->document());
 }
 
 // SLOT connected to action
@@ -822,9 +793,9 @@ void EditorManager::addSaveAndCloseEditorActions(QMenu *contextMenu, OpenEditors
     assignAction(d->m_saveAsCurrentEditorContextAction, ActionManager::command(Constants::SAVEAS)->action());
     assignAction(d->m_revertToSavedCurrentEditorContextAction, ActionManager::command(Constants::REVERTTOSAVED)->action());
 
-    IEditor *editor = entry ? entry->editor : 0;
+    IDocument *document = entry ? entry->document : 0;
 
-    setupSaveActions(editor,
+    setupSaveActions(document,
                      d->m_saveCurrentEditorContextAction,
                      d->m_saveAsCurrentEditorContextAction,
                      d->m_revertToSavedCurrentEditorContextAction);
@@ -955,36 +926,36 @@ void EditorManager::doEscapeKeyFocusMoveMagic()
 
 void EditorManager::saveDocumentFromContextMenu()
 {
-    IEditor *editor = d->m_contextMenuEntry ? d->m_contextMenuEntry->editor : 0;
-    if (editor)
-        saveDocument(editor->document());
+    IDocument *document = d->m_contextMenuEntry ? d->m_contextMenuEntry->document : 0;
+    if (document)
+        saveDocument(document);
 }
 
 void EditorManager::saveDocumentAsFromContextMenu()
 {
-    IEditor *editor = d->m_contextMenuEntry ? d->m_contextMenuEntry->editor : 0;
-    if (editor)
-        saveDocumentAs(editor->document());
+    IDocument *document = d->m_contextMenuEntry ? d->m_contextMenuEntry->document : 0;
+    if (document)
+        saveDocumentAs(document);
 }
 
 void EditorManager::revertToSavedFromContextMenu()
 {
-    IEditor *editor = d->m_contextMenuEntry ? d->m_contextMenuEntry->editor : 0;
-    if (editor)
-        revertToSaved(editor);
+    IDocument *document = d->m_contextMenuEntry ? d->m_contextMenuEntry->document : 0;
+    if (document)
+        revertToSaved(document);
 }
 
 void EditorManager::closeEditorFromContextMenu()
 {
-    IEditor *editor = d->m_contextMenuEntry ? d->m_contextMenuEntry->editor : 0;
-    if (editor)
-        closeEditor(editor);
+    IDocument *document = d->m_contextMenuEntry ? d->m_contextMenuEntry->document : 0;
+    if (document)
+        closeEditors(d->m_editorModel->editorsForDocument(document));
 }
 
 void EditorManager::closeOtherEditorsFromContextMenu()
 {
-    IEditor *editor = d->m_contextMenuEntry ? d->m_contextMenuEntry->editor : 0;
-    closeOtherEditors(editor);
+    IDocument *document = d->m_contextMenuEntry ? d->m_contextMenuEntry->document : 0;
+    closeOtherEditors(document);
 }
 
 void EditorManager::showInGraphicalShell()
@@ -1068,8 +1039,8 @@ void EditorManager::closeEditor(OpenEditorsModel::Entry *entry)
 {
     if (!entry)
         return;
-    if (entry->editor)
-        closeEditor(entry->editor);
+    if (entry->document)
+        closeEditors(d->m_editorModel->editorsForDocument(entry->document));
     else
         d->m_editorModel->removeEntry(entry);
 }
@@ -1082,14 +1053,13 @@ bool EditorManager::closeEditors(const QList<IEditor*> &editorsToClose, bool ask
     EditorView *currentView = currentEditorView();
 
     bool closingFailed = false;
-    QList<IEditor*> acceptedEditors;
+    QSet<IEditor*> acceptedEditors;
+    QSet<IDocument *> acceptedDocuments;
     //ask all core listeners to check whether the editor can be closed
     const QList<ICoreListener *> listeners =
         ExtensionSystem::PluginManager::getObjects<ICoreListener>();
     foreach (IEditor *editor, editorsToClose) {
         bool editorAccepted = true;
-        if (d->m_editorModel->isDuplicate(editor))
-            editor = d->m_editorModel->originalForDuplicate(editor);
         foreach (ICoreListener *listener, listeners) {
             if (!listener->editorAboutToClose(editor)) {
                 editorAccepted = false;
@@ -1097,21 +1067,24 @@ bool EditorManager::closeEditors(const QList<IEditor*> &editorsToClose, bool ask
                 break;
             }
         }
-        if (editorAccepted)
-            acceptedEditors.append(editor);
+        if (editorAccepted) {
+            acceptedEditors += d->m_editorModel->editorsForDocument(editor->document()).toSet();
+            acceptedDocuments.insert(editor->document());
+        }
     }
     if (acceptedEditors.isEmpty())
         return false;
     //ask whether to save modified files
     if (askAboutModifiedEditors) {
         bool cancelled = false;
-        QList<IDocument*> list = DocumentManager::saveModifiedDocuments(documentsForEditors(acceptedEditors), &cancelled);
+        QList<IDocument*> list = DocumentManager::saveModifiedDocuments(acceptedDocuments.toList(), &cancelled);
         if (cancelled)
             return false;
         if (!list.isEmpty()) {
             closingFailed = true;
-            QSet<IEditor*> skipSet = editorsForDocuments(list).toSet();
-            acceptedEditors = acceptedEditors.toSet().subtract(skipSet).toList();
+            acceptedDocuments.subtract(list.toSet());
+            QSet<IEditor*> skipSet = d->m_editorModel->editorsForDocuments(list).toSet();
+            acceptedEditors = acceptedEditors.subtract(skipSet);
         }
     }
     if (acceptedEditors.isEmpty())
@@ -1120,12 +1093,6 @@ bool EditorManager::closeEditors(const QList<IEditor*> &editorsToClose, bool ask
     // close Editor History list
     windowPopup()->setVisible(false);
 
-    // add duplicates
-    QList<IEditor *> duplicates;
-    foreach (IEditor *editor, acceptedEditors)
-        duplicates += d->m_editorModel->duplicatesFor(editor);
-    acceptedEditors += duplicates;
-
     QList<EditorView*> closedViews;
 
     // remove the editors
@@ -1168,14 +1135,18 @@ bool EditorManager::closeEditors(const QList<IEditor*> &editorsToClose, bool ask
             if (entry) {
                 activateEditorForEntry(view, entry, flags);
             } else {
-                const QList<IEditor *> editors = d->m_editorModel->editors();
-                if (!editors.isEmpty())
-                    activateEditor(view, editors.last(), flags);
+                // no "restored" ones, so any entry left should have a document
+                const QList<OpenEditorsModel::Entry *> documents = d->m_editorModel->entries();
+                if (!documents.isEmpty()) {
+                    IDocument *document = documents.last()->document;
+                    if (document)
+                        activateEditorForDocument(view, document, flags);
+                }
             }
         }
     }
 
-    emit editorsClosed(acceptedEditors);
+    emit editorsClosed(acceptedEditors.toList());
 
     foreach (IEditor *editor, acceptedEditors) {
         delete editor;
@@ -1197,50 +1168,6 @@ bool EditorManager::closeEditors(const QList<IEditor*> &editorsToClose, bool ask
     return !closingFailed;
 }
 
-void EditorManager::closeDuplicate(Core::IEditor *editor)
-{
-
-    IEditor *original = editor;
-    if (d->m_editorModel->isDuplicate(editor))
-        original= d->m_editorModel->originalForDuplicate(editor);
-    QList<IEditor *> duplicates = d->m_editorModel->duplicatesFor(original);
-
-    if (duplicates.isEmpty()) {
-        closeEditor(editor);
-        return;
-    }
-
-    if (original== editor)
-        d->m_editorModel->makeOriginal(duplicates.first());
-
-    EditorView *currentView = currentEditorView();
-
-    emit editorAboutToClose(editor);
-
-    if (EditorView *view = viewForEditor(editor)) {
-        removeEditor(editor);
-        view->removeEditor(editor);
-
-        IEditor *newCurrent = view->currentEditor();
-        if (!newCurrent)
-            newCurrent = pickUnusedEditor();
-        if (newCurrent) {
-            activateEditor(view, newCurrent, DoNotChangeCurrentEditor);
-        } else {
-            OpenEditorsModel::Entry *entry = d->m_editorModel->firstRestoredEditor();
-            if (entry)
-                activateEditorForEntry(view, entry, DoNotChangeCurrentEditor);
-        }
-    }
-
-    emit editorsClosed(QList<IEditor*>() << editor);
-    delete editor;
-    if (currentView) {
-        if (IEditor *currentEditor = currentView->currentEditor())
-            activateEditor(currentView, currentEditor);
-    }
-}
-
 Core::IEditor *EditorManager::pickUnusedEditor() const
 {
     foreach (IEditor *editor, openedEditors()) {
@@ -1265,9 +1192,9 @@ void EditorManager::activateEditorForEntry(Internal::EditorView *view, OpenEdito
         setCurrentEditor(0);
         return;
     }
-    IEditor *editor = entry->editor;
-    if (editor)  {
-        activateEditor(view, editor, flags);
+    IDocument *document = entry->document;
+    if (document)  {
+        activateEditorForDocument(view, document, flags);
         return;
     }
 
@@ -1298,6 +1225,7 @@ Core::IEditor *EditorManager::placeEditor(Core::Internal::EditorView *view, Core
         bool duplicateSupported = editor->duplicateSupported();
         if (EditorView *sourceView = viewForEditor(editor)) {
             if (editor != sourceView->currentEditor() || !duplicateSupported) {
+                // pull the IEditor over to the new view
                 sourceView->removeEditor(editor);
                 view->addEditor(editor);
                 view->setCurrentEditor(editor);
@@ -1309,7 +1237,6 @@ Core::IEditor *EditorManager::placeEditor(Core::Internal::EditorView *view, Core
             } else if (duplicateSupported) {
                 editor = duplicateEditor(editor);
                 Q_ASSERT(editor);
-                d->m_editorModel->makeOriginal(editor);
             }
         }
         view->addEditor(editor);
@@ -1475,14 +1402,15 @@ IEditor *EditorManager::createEditor(const Id &editorId, const QString &fileName
     return editor;
 }
 
-void EditorManager::addEditor(IEditor *editor, bool isDuplicate)
+void EditorManager::addEditor(IEditor *editor)
 {
     if (!editor)
         return;
     ICore::addContextObject(editor);
 
-    d->m_editorModel->addEditor(editor, isDuplicate);
-    if (!isDuplicate) {
+    bool isNewDocument = false;
+    d->m_editorModel->addEditor(editor, &isNewDocument);
+    if (isNewDocument) {
         const bool isTemporary = editor->isTemporary();
         const bool addWatcher = !isTemporary;
         DocumentManager::addDocument(editor->document(), addWatcher);
@@ -2035,14 +1963,14 @@ void EditorManager::updateMakeWritableWarning()
     }
 }
 
-void EditorManager::setupSaveActions(IEditor *editor, QAction *saveAction, QAction *saveAsAction, QAction *revertToSavedAction)
+void EditorManager::setupSaveActions(IDocument *document, QAction *saveAction, QAction *saveAsAction, QAction *revertToSavedAction)
 {
-    saveAction->setEnabled(editor != 0 && editor->document()->isModified());
-    saveAsAction->setEnabled(editor != 0 && editor->document()->isSaveAsAllowed());
-    revertToSavedAction->setEnabled(editor != 0
-                                    && !editor->document()->filePath().isEmpty() && editor->document()->isModified());
+    saveAction->setEnabled(document != 0 && document->isModified());
+    saveAsAction->setEnabled(document != 0 && document->isSaveAsAllowed());
+    revertToSavedAction->setEnabled(document != 0
+                                    && !document->filePath().isEmpty() && document->isModified());
 
-    const QString documentName = editor ? editor->document()->displayName() : QString();
+    const QString documentName = document ? document->displayName() : QString();
     QString quotedName;
 
     if (!documentName.isEmpty()) {
@@ -2056,11 +1984,12 @@ void EditorManager::setupSaveActions(IEditor *editor, QAction *saveAction, QActi
 void EditorManager::updateActions()
 {
     IEditor *curEditor = currentEditor();
+    IDocument *curDocument = curEditor ? curEditor->document() : 0;
     int openedCount = d->m_editorModel->openDocumentCount();
 
-    if (curEditor) {
+    if (curDocument) {
         if (HostOsInfo::isMacHost())
-            window()->setWindowModified(curEditor->document()->isModified());
+            window()->setWindowModified(curDocument->isModified());
         updateMakeWritableWarning();
     } else /* curEditor */ if (HostOsInfo::isMacHost()) {
         window()->setWindowModified(false);
@@ -2070,11 +1999,11 @@ void EditorManager::updateActions()
         setCloseSplitEnabled(root, root->isSplitter());
 
     QString quotedName;
-    if (curEditor)
-        quotedName = QLatin1Char('"') + curEditor->document()->displayName() + QLatin1Char('"');
-    setupSaveActions(curEditor, d->m_saveAction, d->m_saveAsAction, d->m_revertToSavedAction);
+    if (curDocument)
+        quotedName = QLatin1Char('"') + curDocument->displayName() + QLatin1Char('"');
+    setupSaveActions(curDocument, d->m_saveAction, d->m_saveAsAction, d->m_revertToSavedAction);
 
-    d->m_closeCurrentEditorAction->setEnabled(curEditor != 0);
+    d->m_closeCurrentEditorAction->setEnabled(curDocument);
     d->m_closeCurrentEditorAction->setText(tr("Close %1").arg(quotedName));
     d->m_closeAllEditorsAction->setEnabled(openedCount > 0);
     d->m_closeOtherEditorsAction->setEnabled(openedCount > 1);
@@ -2139,9 +2068,10 @@ QList<IEditor*> EditorManager::visibleEditors() const
     return editors;
 }
 
+// TODO code using this should probably better use OpenEditorsModel
 QList<IEditor*> EditorManager::openedEditors() const
 {
-    return d->m_editorModel->editors();
+    return d->m_editorModel->oneEditorForEachDocument();
 }
 
 OpenEditorsModel *EditorManager::openedEditorsModel() const
@@ -2232,15 +2162,22 @@ QByteArray EditorManager::saveState() const
     QList<OpenEditorsModel::Entry *> entries = d->m_editorModel->entries();
     int entriesCount = 0;
     foreach (OpenEditorsModel::Entry *entry, entries) {
+        // TODO: isTemporary should move to IDocument
+        IEditor *editor = entry->document
+                ? d->m_editorModel->editorsForDocument(entry->document).first()
+                : 0;
         // The editor may be 0 if it was not loaded yet: In that case it is not temporary
-        if (!entry->editor || !entry->editor->isTemporary())
+        if (!editor || !editor->isTemporary())
             ++entriesCount;
     }
 
     stream << entriesCount;
 
     foreach (OpenEditorsModel::Entry *entry, entries) {
-        if (!entry->editor || !entry->editor->isTemporary())
+        IEditor *editor = entry->document
+                ? d->m_editorModel->editorsForDocument(entry->document).first()
+                : 0;
+        if (!editor || !editor->isTemporary())
             stream << entry->fileName() << entry->displayName() << entry->id();
     }
 
@@ -2352,17 +2289,18 @@ void EditorManager::readSettings()
 
 void EditorManager::revertToSaved()
 {
-    revertToSaved(currentEditor());
+    IEditor *editor = currentEditor();
+    revertToSaved(editor ? editor->document() : 0);
 }
 
-void EditorManager::revertToSaved(Core::IEditor *editor)
+void EditorManager::revertToSaved(Core::IDocument *document)
 {
-    if (!editor)
+    if (!document)
         return;
-    const QString fileName =  editor->document()->filePath();
+    const QString fileName =  document->filePath();
     if (fileName.isEmpty())
         return;
-    if (editor->document()->isModified()) {
+    if (document->isModified()) {
         QMessageBox msgBox(QMessageBox::Question, tr("Revert to Saved"),
                            tr("You will lose your current changes if you proceed reverting %1.").arg(QDir::toNativeSeparators(fileName)),
                            QMessageBox::Yes|QMessageBox::No, ICore::mainWindow());
@@ -2375,7 +2313,7 @@ void EditorManager::revertToSaved(Core::IEditor *editor)
 
     }
     QString errorString;
-    if (!editor->document()->reload(&errorString, IDocument::FlagReload, IDocument::TypeContents))
+    if (!document->reload(&errorString, IDocument::FlagReload, IDocument::TypeContents))
         QMessageBox::critical(ICore::mainWindow(), tr("File Error"), errorString);
 }
 
@@ -2444,7 +2382,7 @@ Core::IEditor *EditorManager::duplicateEditor(Core::IEditor *editor)
     IEditor *duplicate = editor->duplicate(0);
     duplicate->restoreState(editor->saveState());
     emit editorCreated(duplicate, duplicate->document()->filePath());
-    addEditor(duplicate, true);
+    addEditor(duplicate);
     return duplicate;
 }
 
diff --git a/src/plugins/coreplugin/editormanager/editormanager.h b/src/plugins/coreplugin/editormanager/editormanager.h
index 0102abb1e92..35c70bf62c3 100644
--- a/src/plugins/coreplugin/editormanager/editormanager.h
+++ b/src/plugins/coreplugin/editormanager/editormanager.h
@@ -136,9 +136,8 @@ public:
 
     OpenEditorsModel *openedEditorsModel() const;
     void closeEditor(OpenEditorsModel::Entry *entry);
-    void closeOtherEditors(IEditor *editor);
+    void closeOtherEditors(IDocument *document);
 
-    QList<IEditor*> editorsForDocuments(QList<IDocument *> documents) const;
     void addCurrentPositionToNavigationHistory(IEditor *editor = 0, const QByteArray &saveState = QByteArray());
     void cutForwardNavigationHistory();
 
@@ -203,7 +202,7 @@ public slots:
     bool saveDocument(Core::IDocument *documentParam = 0);
     bool saveDocumentAs(Core::IDocument *documentParam = 0);
     void revertToSaved();
-    void revertToSaved(Core::IEditor *editor);
+    void revertToSaved(IDocument *document);
     void closeEditor();
     void closeOtherEditors();
     void doEscapeKeyFocusMoveMagic();
@@ -251,9 +250,8 @@ private:
     virtual ~EditorManager();
     void init();
 
-    QList<IDocument *> documentsForEditors(QList<IEditor *> editors) const;
     static IEditor *createEditor(const Id &id = Id(), const QString &fileName = QString());
-    void addEditor(IEditor *editor, bool isDuplicate = false);
+    void addEditor(IEditor *editor);
     void removeEditor(IEditor *editor);
 
     void restoreEditorState(IEditor *editor);
@@ -273,7 +271,6 @@ private:
     static Internal::SplitterOrView *findRoot(const Internal::EditorView *view, int *rootIndex = 0);
 
     void closeEditor(IEditor *editor);
-    void closeDuplicate(IEditor *editor);
     void closeView(Internal::EditorView *view);
     void emptyView(Internal::EditorView *view);
     static void splitNewWindow(Internal::EditorView *view);
@@ -282,7 +279,7 @@ private:
     void updateAutoSave();
     void setCloseSplitEnabled(Internal::SplitterOrView *splitterOrView, bool enable);
     void updateMakeWritableWarning();
-    void setupSaveActions(IEditor *editor, QAction *saveAction, QAction *saveAsAction, QAction *revertToSavedAction);
+    void setupSaveActions(IDocument *document, QAction *saveAction, QAction *saveAsAction, QAction *revertToSavedAction);
 
     friend class Core::Internal::MainWindow;
     friend class Core::Internal::SplitterOrView;
diff --git a/src/plugins/coreplugin/editormanager/openeditorsmodel.cpp b/src/plugins/coreplugin/editormanager/openeditorsmodel.cpp
index 33efe4032c6..e5ebf33f67f 100644
--- a/src/plugins/coreplugin/editormanager/openeditorsmodel.cpp
+++ b/src/plugins/coreplugin/editormanager/openeditorsmodel.cpp
@@ -45,8 +45,8 @@ struct OpenEditorsModelPrivate
     const QIcon m_lockedIcon;
     const QIcon m_unlockedIcon;
 
-    QList<OpenEditorsModel::Entry *> m_editors;
-    QList<IEditor *> m_duplicateEditors;
+    QList<OpenEditorsModel::Entry *> m_documents;
+    QMap<IDocument *, QList<IEditor *> > m_editors;
 };
 
 OpenEditorsModelPrivate::OpenEditorsModelPrivate() :
@@ -56,7 +56,7 @@ OpenEditorsModelPrivate::OpenEditorsModelPrivate() :
 }
 
 OpenEditorsModel::Entry::Entry() :
-    editor(0)
+    document(0)
 {
 }
 
@@ -81,16 +81,16 @@ QIcon OpenEditorsModel::unlockedIcon() const
 }
 
 QString OpenEditorsModel::Entry::fileName() const {
-    return editor ? editor->document()->filePath() : m_fileName;
+    return document ? document->filePath() : m_fileName;
 }
 
 QString OpenEditorsModel::Entry::displayName() const {
-    return editor ? editor->document()->displayName() : m_displayName;
+    return document ? document->displayName() : m_displayName;
 }
 
 Id OpenEditorsModel::Entry::id() const
 {
-    return editor ? editor->id() : m_id;
+    return m_id;
 }
 
 int OpenEditorsModel::columnCount(const QModelIndex &parent) const
@@ -103,31 +103,32 @@ int OpenEditorsModel::columnCount(const QModelIndex &parent) const
 int OpenEditorsModel::rowCount(const QModelIndex &parent) const
 {
     if (!parent.isValid())
-        return d->m_editors.count() + 1/*<no document>*/;
+        return d->m_documents.count() + 1/*<no document>*/;
     return 0;
 }
 
-QList<IEditor *> OpenEditorsModel::editors() const
+// TODO remove
+QList<IEditor *> OpenEditorsModel::oneEditorForEachDocument() const
 {
     QList<IEditor *> result;
-    foreach (const Entry *entry, d->m_editors)
-        if (entry->editor)
-            result += entry->editor;
+    QMapIterator<IDocument *, QList<IEditor *> > it(d->m_editors);
+    while (it.hasNext())
+        result << it.next().value().first();
     return result;
 }
 
-void OpenEditorsModel::addEditor(IEditor *editor, bool isDuplicate)
+void OpenEditorsModel::addEditor(IEditor *editor, bool *isNewDocument)
 {
     if (!editor)
         return;
 
-    if (isDuplicate) {
-        d->m_duplicateEditors.append(editor);
-        return;
-    }
-
+    QList<IEditor *> &editorList = d->m_editors[editor->document()];
+    if (isNewDocument)
+        *isNewDocument = editorList.isEmpty();
+    editorList << editor;
     Entry *entry = new Entry;
-    entry->editor = editor;
+    entry->document = editor->document();
+    entry->m_id = editor->id();
     addEntry(entry);
 }
 
@@ -142,9 +143,9 @@ void OpenEditorsModel::addRestoredEditor(const QString &fileName, const QString
 
 OpenEditorsModel::Entry *OpenEditorsModel::firstRestoredEditor() const
 {
-    for (int i = 0; i < d->m_editors.count(); ++i)
-        if (!d->m_editors.at(i)->editor)
-            return d->m_editors.at(i);
+    for (int i = 0; i < d->m_documents.count(); ++i)
+        if (!d->m_documents.at(i)->document)
+            return d->m_documents.at(i);
     return 0;
 }
 
@@ -152,43 +153,34 @@ void OpenEditorsModel::addEntry(Entry *entry)
 {
     QString fileName = entry->fileName();
 
+    // replace a non-loaded entry (aka 'restored') if possible
     int previousIndex = findFileName(fileName);
     if (previousIndex >= 0) {
-        if (entry->editor && d->m_editors.at(previousIndex)->editor == 0) {
-            d->m_editors[previousIndex] = entry;
-            connect(entry->editor->document(), SIGNAL(changed()), this, SLOT(itemChanged()));
+        if (entry->document && d->m_documents.at(previousIndex)->document == 0) {
+            d->m_documents[previousIndex] = entry;
+            connect(entry->document, SIGNAL(changed()), this, SLOT(itemChanged()));
         }
         return;
     }
 
     int index;
     QString displayName = entry->displayName();
-    for (index = 0; index < d->m_editors.count(); ++index) {
-        if (displayName < d->m_editors.at(index)->displayName())
+    for (index = 0; index < d->m_documents.count(); ++index) {
+        if (displayName < d->m_documents.at(index)->displayName())
             break;
     }
     int row = index + 1/*<no document>*/;
     beginInsertRows(QModelIndex(), row, row);
-    d->m_editors.insert(index, entry);
-    if (entry->editor)
-        connect(entry->editor->document(), SIGNAL(changed()), this, SLOT(itemChanged()));
+    d->m_documents.insert(index, entry);
+    if (entry->document)
+        connect(entry->document, SIGNAL(changed()), this, SLOT(itemChanged()));
     endInsertRows();
 }
 
 int OpenEditorsModel::findDocument(IDocument *document) const
 {
-    for (int i = 0; i < d->m_editors.count(); ++i) {
-        IEditor *editor = d->m_editors.at(i)->editor;
-        if (editor && editor->document() == document)
-            return i;
-    }
-    return -1;
-}
-
-int OpenEditorsModel::findEditor(IEditor *editor) const
-{
-    for (int i = 0; i < d->m_editors.count(); ++i)
-        if (d->m_editors.at(i)->editor == editor)
+    for (int i = 0; i < d->m_documents.count(); ++i)
+        if (d->m_documents.at(i)->document == document)
             return i;
     return -1;
 }
@@ -197,8 +189,8 @@ int OpenEditorsModel::findFileName(const QString &filename) const
 {
     if (filename.isEmpty())
         return -1;
-    for (int i = 0; i < d->m_editors.count(); ++i) {
-        if (d->m_editors.at(i)->fileName() == filename)
+    for (int i = 0; i < d->m_documents.count(); ++i) {
+        if (d->m_documents.at(i)->fileName() == filename)
             return i;
     }
     return -1;
@@ -206,116 +198,107 @@ int OpenEditorsModel::findFileName(const QString &filename) const
 
 void OpenEditorsModel::removeEntry(OpenEditorsModel::Entry *entry)
 {
-    int index = d->m_editors.indexOf(entry);
-    removeEditor(index);
+    QTC_ASSERT(!entry->document, return); // we wouldn't know what to do with the associated editors
+    int index = d->m_documents.indexOf(entry);
+    removeDocument(index);
 }
 
-void OpenEditorsModel::removeEditor(IEditor *editor)
+void OpenEditorsModel::removeEditor(IEditor *editor, bool *lastOneForDocument)
 {
-    d->m_duplicateEditors.removeAll(editor);
-    removeEditor(findEditor(editor));
+    if (lastOneForDocument)
+        *lastOneForDocument = false;
+    QTC_ASSERT(editor, return);
+    IDocument *document = editor->document();
+    QTC_ASSERT(d->m_editors.contains(document), return);
+    d->m_editors[document].removeAll(editor);
+    if (d->m_editors.value(document).isEmpty()) {
+        if (lastOneForDocument)
+            *lastOneForDocument = true;
+        d->m_editors.remove(document);
+        removeDocument(findDocument(document));
+    }
 }
 
-void OpenEditorsModel::removeEditor(const QString &fileName)
+void OpenEditorsModel::removeDocument(const QString &fileName)
 {
-    removeEditor(findFileName(fileName));
+    int index = findFileName(fileName);
+    QTC_ASSERT(!d->m_documents.at(index)->document, return); // we wouldn't know what to do with the associated editors
+    removeDocument(index);
 }
 
-void OpenEditorsModel::removeEditor(int idx)
+void OpenEditorsModel::removeDocument(int idx)
 {
     if (idx < 0)
         return;
-    QTC_ASSERT(idx < d->m_editors.size(), return);
-    IEditor *editor = d->m_editors.at(idx)->editor;
+    QTC_ASSERT(idx < d->m_documents.size(), return);
+    IDocument *document = d->m_documents.at(idx)->document;
     int row = idx + 1/*<no document>*/;
     beginRemoveRows(QModelIndex(), row, row);
-    d->m_editors.removeAt(idx);
+    d->m_documents.removeAt(idx);
     endRemoveRows();
-    if (editor)
-        disconnect(editor->document(), SIGNAL(changed()), this, SLOT(itemChanged()));
+    if (document)
+        disconnect(document, SIGNAL(changed()), this, SLOT(itemChanged()));
 }
 
 void OpenEditorsModel::removeAllRestoredEditors()
 {
-    for (int i = d->m_editors.count()-1; i >= 0; --i) {
-        if (!d->m_editors.at(i)->editor) {
+    for (int i = d->m_documents.count()-1; i >= 0; --i) {
+        if (!d->m_documents.at(i)->document) {
             int row = i + 1/*<no document>*/;
             beginRemoveRows(QModelIndex(), row, row);
-            d->m_editors.removeAt(i);
+            d->m_documents.removeAt(i);
             endRemoveRows();
         }
     }
 }
 
-bool OpenEditorsModel::isDuplicate(IEditor *editor) const
+QList<IEditor *> OpenEditorsModel::editorsForDocument(IDocument *document) const
 {
-    return editor && d->m_duplicateEditors.contains(editor);
+    return d->m_editors.value(document);
 }
 
-IEditor *OpenEditorsModel::originalForDuplicate(IEditor *duplicate) const
-{
-    IDocument *document = duplicate->document();
-    foreach (const Entry *e, d->m_editors)
-        if (e->editor && e->editor->document() == document)
-            return e->editor;
-    return 0;
-}
-
-QList<IEditor *> OpenEditorsModel::duplicatesFor(IEditor *editor) const
+QList<IEditor *> OpenEditorsModel::editorsForDocuments(const QList<IDocument *> &documents) const
 {
     QList<IEditor *> result;
-    IDocument *document = editor->document();
-    foreach (IEditor *e, d->m_duplicateEditors)
-        if (e->document() == document)
-            result += e;
+    foreach (IDocument *document, documents)
+        result += d->m_editors.value(document);
     return result;
 }
 
-void OpenEditorsModel::makeOriginal(IEditor *duplicate)
+int OpenEditorsModel::indexOfDocument(IDocument *document) const
 {
-    Q_ASSERT(duplicate && isDuplicate(duplicate));
-    IEditor *original = originalForDuplicate(duplicate);
-    Q_ASSERT(original);
-    int i = findEditor(original);
-    d->m_editors[i]->editor = duplicate;
-    d->m_duplicateEditors.removeOne(duplicate);
-    d->m_duplicateEditors.append(original);
-}
-
-int OpenEditorsModel::indexOfEditor(IEditor *editor) const
-{
-    if (!editor)
+    if (!document)
         return -1;
-    return findEditor(editor);
+    return findDocument(document);
 }
 
 QModelIndex OpenEditorsModel::index(int row, int column, const QModelIndex &parent) const
 {
     Q_UNUSED(parent)
-    if (column < 0 || column > 1 || row < 0 || row >= d->m_editors.count() + 1/*<no document>*/)
+    if (column < 0 || column > 1 || row < 0 || row >= d->m_documents.count() + 1/*<no document>*/)
         return QModelIndex();
     return createIndex(row, column);
 }
 
 OpenEditorsModel::Entry *OpenEditorsModel::entryAtRow(int row) const
 {
-    int editorIndex = row - 1/*<no document>*/;
-    if (editorIndex < 0)
+    int entryIndex = row - 1/*<no document>*/;
+    if (entryIndex < 0)
         return 0;
-    return d->m_editors[editorIndex];
+    return d->m_documents[entryIndex];
 }
 
 int OpenEditorsModel::openDocumentCount() const
 {
-    return d->m_editors.count();
+    return d->m_documents.count();
 }
 
 QVariant OpenEditorsModel::data(const QModelIndex &index, int role) const
 {
     if (!index.isValid() || (index.column() != 0 && role < Qt::UserRole))
         return QVariant();
-    int editorIndex = index.row() - 1/*<no document>*/;
-    if (editorIndex < 0) {
+    int entryIndex = index.row() - 1/*<no document>*/;
+    if (entryIndex < 0) {
         // <no document> entry
         switch (role) {
         case Qt::DisplayRole:
@@ -326,19 +309,19 @@ QVariant OpenEditorsModel::data(const QModelIndex &index, int role) const
             return QVariant();
         }
     }
-    const Entry *e = d->m_editors.at(editorIndex);
+    const Entry *e = d->m_documents.at(entryIndex);
     switch (role) {
     case Qt::DisplayRole:
-        return (e->editor && e->editor->document()->isModified())
+        return (e->document && e->document->isModified())
                 ? e->displayName() + QLatin1Char('*')
                 : e->displayName();
     case Qt::DecorationRole:
     {
         bool showLock = false;
-        if (e->editor) {
-            showLock = e->editor->document()->filePath().isEmpty()
+        if (e->document) {
+            showLock = e->document->filePath().isEmpty()
                     ? false
-                    : e->editor->document()->isFileReadOnly();
+                    : e->document->isFileReadOnly();
         } else {
             showLock = !QFileInfo(e->m_fileName).isWritable();
         }
@@ -348,23 +331,17 @@ QVariant OpenEditorsModel::data(const QModelIndex &index, int role) const
         return e->fileName().isEmpty()
                 ? e->displayName()
                 : QDir::toNativeSeparators(e->fileName());
-    case Qt::UserRole:
-        return qVariantFromValue(e->editor);
-    case Qt::UserRole + 1:
-        return e->fileName();
-    case Qt::UserRole + 2:
-        return QVariant::fromValue(e->editor ? Core::Id(e->editor->id()) : e->id());
     default:
         return QVariant();
     }
     return QVariant();
 }
 
-int OpenEditorsModel::rowOfEditor(IEditor *editor) const
+int OpenEditorsModel::rowOfDocument(IDocument *document) const
 {
-    if (!editor)
+    if (!document)
         return 0 /*<no document>*/;
-    return findEditor(originalForDuplicate(editor)) + 1/*<no document>*/;
+    return findDocument(document) + 1/*<no document>*/;
 }
 
 void OpenEditorsModel::itemChanged()
@@ -380,7 +357,7 @@ void OpenEditorsModel::itemChanged()
 
 QList<OpenEditorsModel::Entry *> OpenEditorsModel::entries() const
 {
-    return d->m_editors;
+    return d->m_documents;
 }
 
 } // namespace Core
diff --git a/src/plugins/coreplugin/editormanager/openeditorsmodel.h b/src/plugins/coreplugin/editormanager/openeditorsmodel.h
index 0df21296c69..4ff45592284 100644
--- a/src/plugins/coreplugin/editormanager/openeditorsmodel.h
+++ b/src/plugins/coreplugin/editormanager/openeditorsmodel.h
@@ -62,7 +62,7 @@ public:
 
     struct CORE_EXPORT Entry {
         Entry();
-        IEditor *editor;
+        IDocument *document;
         QString fileName() const;
         QString displayName() const;
         Id id() const;
@@ -72,38 +72,34 @@ public:
     };
 
     Entry *entryAtRow(int row) const;
-    int rowOfEditor(IEditor *editor) const;
+    int rowOfDocument(IDocument *document) const;
 
     int openDocumentCount() const;
 
-    void addEditor(IEditor *editor, bool isDuplicate = false);
-    void addRestoredEditor(const QString &fileName, const QString &displayName, const Id &id);
-    Entry *firstRestoredEditor() const;
-
     QList<Entry *> entries() const;
 
+    QList<IEditor *> editorsForDocument(IDocument *document) const;
+    QList<IEditor *> editorsForDocuments(const QList<IDocument *> &documents) const;
+    QList<IEditor *> oneEditorForEachDocument() const;
+    int indexOfDocument(IDocument *document) const;
+
+    // editor manager related methods, nobody else should call it
+    void addEditor(IEditor *editor, bool *isNewDocument);
+    void addRestoredEditor(const QString &fileName, const QString &displayName, const Id &id);
+    Entry *firstRestoredEditor() const;
     void removeEntry(Entry *entry);
-    void removeEditor(IEditor *editor);
-    void removeEditor(const QString &fileName);
-
+    void removeEditor(IEditor *editor, bool *lastOneForDocument);
+    void removeDocument(const QString &fileName);
     void removeAllRestoredEditors();
 
-    QList<IEditor *> editors() const;
-    bool isDuplicate(IEditor *editor) const;
-    QList<IEditor *> duplicatesFor(IEditor *editor) const;
-    IEditor *originalForDuplicate(IEditor *duplicate) const;
-    void makeOriginal(IEditor *duplicate);
-    int indexOfEditor(IEditor *editor) const;
-
 private slots:
     void itemChanged();
 
 private:
     void addEntry(Entry *entry);
     int findDocument(IDocument *document) const;
-    int findEditor(IEditor *editor) const;
     int findFileName(const QString &filename) const;
-    void removeEditor(int idx);
+    void removeDocument(int idx);
 
     OpenEditorsModelPrivate *d;
 };
diff --git a/src/plugins/coreplugin/editormanager/openeditorsview.cpp b/src/plugins/coreplugin/editormanager/openeditorsview.cpp
index 46cb926c68e..cf9ce1c679d 100644
--- a/src/plugins/coreplugin/editormanager/openeditorsview.cpp
+++ b/src/plugins/coreplugin/editormanager/openeditorsview.cpp
@@ -29,6 +29,7 @@
 
 #include "openeditorsview.h"
 #include "editormanager.h"
+#include "ieditor.h"
 #include "openeditorsmodel.h"
 
 #include <coreplugin/coreconstants.h>
@@ -126,8 +127,9 @@ OpenEditorsWidget::~OpenEditorsWidget()
 
 void OpenEditorsWidget::updateCurrentItem(Core::IEditor *editor)
 {
+    IDocument *document = editor ? editor->document() : 0;
     EditorManager *em = EditorManager::instance();
-    QModelIndex index = m_model->index(em->openedEditorsModel()->indexOfEditor(editor), 0);
+    QModelIndex index = m_model->index(em->openedEditorsModel()->indexOfDocument(document), 0);
     if (!index.isValid()) {
         clearSelection();
         return;
diff --git a/src/plugins/coreplugin/editormanager/openeditorswindow.cpp b/src/plugins/coreplugin/editormanager/openeditorswindow.cpp
index 0b1629dade4..a43166e6d49 100644
--- a/src/plugins/coreplugin/editormanager/openeditorswindow.cpp
+++ b/src/plugins/coreplugin/editormanager/openeditorswindow.cpp
@@ -204,7 +204,7 @@ void OpenEditorsWindow::setEditors(const QList<EditLocation> &globalHistory, Edi
 
     // add purely restored editors which are not initialised yet
     foreach (OpenEditorsModel::Entry *entry, model->entries()) {
-        if (entry->editor)
+        if (entry->document)
             continue;
         QTreeWidgetItem *item = new QTreeWidgetItem();
         QString title = entry->displayName();
@@ -229,7 +229,7 @@ void OpenEditorsWindow::selectEditor(QTreeWidgetItem *item)
     } else {
         if (!EditorManager::openEditor(
                     item->toolTip(0), item->data(0, Qt::UserRole+2).value<Core::Id>())) {
-            EditorManager::instance()->openedEditorsModel()->removeEditor(item->toolTip(0));
+            EditorManager::instance()->openedEditorsModel()->removeDocument(item->toolTip(0));
             delete item;
         }
     }
diff --git a/src/plugins/coreplugin/editortoolbar.cpp b/src/plugins/coreplugin/editortoolbar.cpp
index 905d3e68ecf..3fb29a3a2e7 100644
--- a/src/plugins/coreplugin/editortoolbar.cpp
+++ b/src/plugins/coreplugin/editortoolbar.cpp
@@ -290,7 +290,8 @@ void EditorToolBar::setToolbarCreationFlags(ToolbarCreationFlags flags)
 
 void EditorToolBar::setCurrentEditor(IEditor *editor)
 {
-    d->m_editorList->setCurrentIndex(d->m_editorsListModel->rowOfEditor(editor));
+    IDocument *document = editor ? editor->document() : 0;
+    d->m_editorList->setCurrentIndex(d->m_editorsListModel->rowOfDocument(document));
 
     // If we never added the toolbar from the editor,  we will never change
     // the editor, so there's no need to update the toolbar either.
@@ -303,7 +304,7 @@ void EditorToolBar::setCurrentEditor(IEditor *editor)
 void EditorToolBar::updateEditorListSelection(IEditor *newSelection)
 {
     if (newSelection)
-        d->m_editorList->setCurrentIndex(d->m_editorsListModel->rowOfEditor(newSelection));
+        d->m_editorList->setCurrentIndex(d->m_editorsListModel->rowOfDocument(newSelection->document()));
 }
 
 void EditorToolBar::changeActiveEditor(int row)
@@ -375,7 +376,7 @@ void EditorToolBar::updateEditorStatus(IEditor *editor)
         return;
     }
 
-    d->m_editorList->setCurrentIndex(d->m_editorsListModel->rowOfEditor(editor));
+    d->m_editorList->setCurrentIndex(d->m_editorsListModel->rowOfDocument(editor->document()));
 
     if (editor->document()->filePath().isEmpty()) {
         d->m_lockButton->setIcon(QIcon());
diff --git a/src/plugins/fakevim/fakevimplugin.cpp b/src/plugins/fakevim/fakevimplugin.cpp
index 1e68d0e6019..6261728c458 100644
--- a/src/plugins/fakevim/fakevimplugin.cpp
+++ b/src/plugins/fakevim/fakevimplugin.cpp
@@ -1999,7 +1999,9 @@ int FakeVimPluginPrivate::currentFile() const
 {
     OpenEditorsModel *model = EditorManager::instance()->openedEditorsModel();
     IEditor *editor = EditorManager::currentEditor();
-    return model->indexOfEditor(editor);
+    if (!editor)
+        return -1;
+    return model->indexOfDocument(editor->document());
 }
 
 void FakeVimPluginPrivate::switchToFile(int n)