nicer visual session switching

src/plugins/coreplugin/editormanager/editormanager.cpp

@@ -1538,6 +1538,7 @@ QByteArray EditorManager::saveState() const
 bool EditorManager::restoreState(const QByteArray &state)
 {
     closeAllEditors(true);
+    removeAllSplits();
     QDataStream stream(state);
 
     QByteArray version;

src/plugins/coreplugin/editormanager/editormanager.h

@@ -208,6 +208,8 @@ private slots:
     void goBackInNavigationHistory();
     void goForwardInNavigationHistory();
     void makeCurrentEditorWritable();
+
+public slots:
     void split(Qt::Orientation orientation);
     void split();
     void splitSideBySide();