diff --git a/src/plugins/cpptools/cppmodelmanager.cpp b/src/plugins/cpptools/cppmodelmanager.cpp
index cc1979d6b70..d9f53f2f5d2 100644
--- a/src/plugins/cpptools/cppmodelmanager.cpp
+++ b/src/plugins/cpptools/cppmodelmanager.cpp
@@ -714,9 +714,28 @@ void CppModelManager::GC()
     if (!m_enableGC)
         return;
 
-    const Snapshot currentSnapshot = snapshot();
+    // Collect files of CppEditorSupport and AbstractEditorSupport.
+    QStringList filesInEditorSupports;
+    QList<CppEditorSupport *> cppEditorSupports;
+    {
+        QMutexLocker locker(&m_cppEditorSupportsMutex);
+        cppEditorSupports = m_cppEditorSupports.values();
+    }
+    foreach (const CppEditorSupport *cppEditorSupport, cppEditorSupports)
+        filesInEditorSupports << cppEditorSupport->fileName();
+
+    QSetIterator<AbstractEditorSupport *> jt(m_extraEditorSupports);
+    while (jt.hasNext()) {
+        AbstractEditorSupport *abstractEditorSupport = jt.next();
+        filesInEditorSupports << abstractEditorSupport->fileName();
+    }
+
+    Snapshot currentSnapshot = snapshot();
     QSet<QString> reachableFiles;
-    QStringList todo = projectFiles();
+    // The configuration file is part of the project files, which is just fine.
+    // If single files are open, without any project, then there is no need to
+    // keep the configuration file around.
+    QStringList todo = filesInEditorSupports + projectFiles();
 
     // Collect all files that are reachable from the project files
     while (!todo.isEmpty()) {
diff --git a/src/plugins/cpptools/cppmodelmanager.h b/src/plugins/cpptools/cppmodelmanager.h
index a8ca3ee1a03..5c65a9781ad 100644
--- a/src/plugins/cpptools/cppmodelmanager.h
+++ b/src/plugins/cpptools/cppmodelmanager.h
@@ -151,11 +151,11 @@ public slots:
 
 private slots:
     // This should be executed in the GUI thread.
-    void onAboutToRemoveProject(ProjectExplorer::Project *project);
     void onAboutToLoadSession();
     void onAboutToUnloadSession();
-    void onCoreAboutToClose();
     void onProjectAdded(ProjectExplorer::Project *project);
+    void onAboutToRemoveProject(ProjectExplorer::Project *project);
+    void onCoreAboutToClose();
 
 private:
     void delayedGC();
diff --git a/src/plugins/cpptools/cppmodelmanager_test.cpp b/src/plugins/cpptools/cppmodelmanager_test.cpp
index 7e649a9c014..1fb02ba5ed1 100644
--- a/src/plugins/cpptools/cppmodelmanager_test.cpp
+++ b/src/plugins/cpptools/cppmodelmanager_test.cpp
@@ -551,3 +551,38 @@ void CppToolsPlugin::test_modelmanager_gc_if_last_cppeditor_closed()
     QVERIFY(!mm->workingCopy().contains(file));
     QVERIFY(!mm->snapshot().contains(file));
 }
+
+/// Check: Files that are open in the editor are not garbage collected.
+void CppToolsPlugin::test_modelmanager_dont_gc_opened_files()
+{
+    ModelManagerTestHelper helper;
+
+    TestDataDirectory testDataDirectory(QLatin1String("testdata_guiproject1"));
+    const QString file = testDataDirectory.file(QLatin1String("main.cpp"));
+
+    Core::EditorManager *em = Core::EditorManager::instance();
+    CppModelManager *mm = CppModelManager::instance();
+
+    // Open a file in the editor
+    QCOMPARE(Core::EditorManager::documentModel()->openedDocuments().size(), 0);
+    Core::IEditor *editor = em->openEditor(file);
+    QVERIFY(editor);
+    QCOMPARE(Core::EditorManager::documentModel()->openedDocuments().size(), 1);
+    QVERIFY(mm->isCppEditor(editor));
+
+    // Check: File is in the working copy and snapshot
+    QVERIFY(mm->workingCopy().contains(file));
+    QVERIFY(mm->snapshot().contains(file));
+
+    // Run the garbage collector
+    mm->GC();
+
+    // Check: File is still there
+    QVERIFY(mm->workingCopy().contains(file));
+    QVERIFY(mm->snapshot().contains(file));
+
+    // Close editor
+    em->closeEditors(QList<Core::IEditor*>() << editor);
+    helper.waitForFinishedGc();
+    QVERIFY(mm->snapshot().isEmpty());
+}
diff --git a/src/plugins/cpptools/cpptoolsplugin.h b/src/plugins/cpptools/cpptoolsplugin.h
index 7b6ae5aad05..de48a8fe218 100644
--- a/src/plugins/cpptools/cpptoolsplugin.h
+++ b/src/plugins/cpptools/cpptoolsplugin.h
@@ -195,6 +195,7 @@ private slots:
     void test_modelmanager_snapshot_after_two_projects();
     void test_modelmanager_extraeditorsupport_uiFiles();
     void test_modelmanager_gc_if_last_cppeditor_closed();
+    void test_modelmanager_dont_gc_opened_files();
 
 private:
     void test_completion();