diff --git a/src/cantor.cpp b/src/cantor.cpp
index 8f1e5fe723f115c55d3dea5ca2a7c98c16ecf83e..e8d951c3bc4d9c360c32d1b110b11737a21d9d89 100644
--- a/src/cantor.cpp
+++ b/src/cantor.cpp
@@ -48,8 +48,9 @@
 #include "settings.h"
 #include "ui_settings.h"
 #include "backendchoosedialog.h"
+#include <QMetaObject>
 
-CantorShell::CantorShell() : KParts::MainWindow(), m_part(nullptr)
+CantorShell::CantorShell() : KParts::MainWindow(), m_part(nullptr), m_panelHandler(nullptr)
 {
     // set the shell's ui resource file
     setXMLFile(QLatin1String("cantor_shell.rc"));
@@ -75,6 +76,8 @@ CantorShell::CantorShell() : KParts::MainWindow(), m_part(nullptr)
 
     setDockOptions(QMainWindow::AnimatedDocks|QMainWindow::AllowTabbedDocks|QMainWindow::VerticalTabs);
 
+    initPanels();
+
     updateNewSubmenu();
 }
 
@@ -358,7 +361,7 @@ void CantorShell::addWorksheet(const QString& backendName)
         {
             connect(part, SIGNAL(setCaption(QString,QIcon)), this, SLOT(setTabCaption(QString,QIcon)));
             connect(part, SIGNAL(worksheetSave(QUrl)), this, SLOT(onWorksheetSave(QUrl)));
-            connect(part, SIGNAL(requestOpenWorksheet(QUrl)), this, SLOT(load(QUrl)));
+            connect(part, SIGNAL(showHelp(QString)), this, SIGNAL(showHelp(QString)));
             m_parts.append(part);
             if (backend) // If backend empty (loading worksheet from file), then we connect to signal and wait
                 m_parts2Backends[part] = backend->id();
@@ -396,11 +399,7 @@ void CantorShell::addWorksheet(const QString& backendName)
 
 void CantorShell::activateWorksheet(int index)
 {
-    QObject* pluginHandler=m_part->findChild<QObject*>(QLatin1String("PanelPluginHandler"));
-    if (pluginHandler)
-        disconnect(pluginHandler,SIGNAL(pluginsChanged()), this, SLOT(updatePanel()));
-
-    // Save part state before change worksheet
+    // Save part panels states before change worksheet
     if (m_part)
     {
         QStringList visiblePanelNames;
@@ -410,6 +409,16 @@ void CantorShell::activateWorksheet(int index)
                 visiblePanelNames << doc->objectName();
         }
         m_pluginsVisibility[m_part] = visiblePanelNames;
+
+        Cantor::WorksheetAccessInterface* wa=m_part->findChild<Cantor::WorksheetAccessInterface*>(Cantor::WorksheetAccessInterface::Name);
+        assert(wa);
+        PanelStates states;
+        QList<Cantor::PanelPlugin*> plugins=m_panelHandler.plugins(wa->session());
+        for(Cantor::PanelPlugin* plugin : plugins)
+        {
+            states.insert(plugin->name(), plugin->saveState());
+        }
+        m_pluginsStates[m_part] = states;
     }
 
     m_part=findPart(m_tabWidget->widget(index));
@@ -418,8 +427,6 @@ void CantorShell::activateWorksheet(int index)
         createGUI(m_part);
 
         updateWindowTitle(m_part->url().fileName());
-        QObject* pluginHandler=m_part->findChild<QObject*>(QLatin1String("PanelPluginHandler"));
-        connect(pluginHandler, SIGNAL(pluginsChanged()), this, SLOT(updatePanel()));
         updatePanel();
     }
     else
@@ -482,6 +489,7 @@ void CantorShell::closeTab(int index)
 
     m_tabWidget->removeTab(index);
 
+    bool isCurrectPartClosed = m_part ? widget == m_part->widget() : false;
     if(widget->objectName()==QLatin1String("ErrorMessage"))
     {
         widget->deleteLater();
@@ -495,13 +503,16 @@ void CantorShell::closeTab(int index)
             m_parts.removeAll(part);
             m_pluginsVisibility.remove(part);
             m_parts2Backends.remove(part);
+            m_pluginsStates.remove(part);
             delete part;
         }
     }
 
     if (m_tabWidget->count() == 0)
         setCaption(QString());
-    updatePanel();
+
+    if (isCurrectPartClosed || m_part == nullptr)
+        updatePanel();
 }
 
 bool CantorShell::reallyClose(bool checkAllParts) {
@@ -645,35 +656,46 @@ KParts::ReadWritePart* CantorShell::findPart(QWidget* widget)
     return nullptr;
 }
 
-void CantorShell::updatePanel()
+void CantorShell::initPanels()
 {
-    unplugActionList(QLatin1String("view_show_panel_list"));
+    m_panelHandler.loadPlugins();
 
-    //remove all of the previous panels (but do not delete the widgets)
-    foreach(QDockWidget* dock, m_panels)
+    QList<Cantor::PanelPlugin*> plugins = m_panelHandler.allPlugins();
+    foreach(Cantor::PanelPlugin* plugin, plugins)
     {
-        QWidget* widget=dock->widget();
-        if(widget!=nullptr)
+        if(plugin==nullptr)
         {
-            widget->setParent(this);
-            widget->hide();
+            qDebug()<<"somethings wrong";
+            continue;
         }
-        dock->deleteLater();
-    }
-    m_panels.clear();
 
-    QList<QAction*> panelActions;
+        qDebug()<<"adding panel for "<<plugin->name();
+        plugin->setParentWidget(this);
+        plugin->connectToShell(this);
+
+        QDockWidget* docker=new QDockWidget(plugin->name(), this);
+        docker->setObjectName(plugin->name());
+        docker->setWidget(plugin->widget());
+        addDockWidget ( Qt::RightDockWidgetArea,  docker );
+
+        docker->hide();
+
+        connect(plugin, &Cantor::PanelPlugin::visibilityRequested, this, &CantorShell::pluginVisibilityRequested);
+        connect(plugin, &Cantor::PanelPlugin::requestRunCommand, this, &CantorShell::pluginCommandRunRequested);
+
+        m_panels.append(docker);
 
-    Cantor::PanelPluginHandler* handler=m_part->findChild<Cantor::PanelPluginHandler*>(QLatin1String("PanelPluginHandler"));
-    if(!handler)
-    {
-        qDebug()<<"no PanelPluginHandle found for this part";
-        return;
     }
+}
 
-    QDockWidget* last=nullptr;
-    bool isNewWorksheet = !m_pluginsVisibility.contains(m_part);
 
+void CantorShell::updatePanel()
+{
+    unplugActionList(QLatin1String("view_show_panel_list"));
+
+    QList<QAction*> panelActions;
+
+    bool isNewWorksheet = !m_pluginsVisibility.contains(m_part);
     if (isNewWorksheet)
     {
         KConfigGroup panelStatusGroup(KSharedConfig::openConfig(), QLatin1String("PanelsStatus"));
@@ -685,50 +707,86 @@ void CantorShell::updatePanel()
         }
     }
 
-    QList<Cantor::PanelPlugin*> plugins=handler->plugins();
-    foreach(Cantor::PanelPlugin* plugin, plugins)
+    Cantor::WorksheetAccessInterface* wa = nullptr;
+    if (m_part)
+        wa = m_part->findChild<Cantor::WorksheetAccessInterface*>(Cantor::WorksheetAccessInterface::Name);
+
+    // Worksheet interface can be missing on m_part clossing (and m_part on this moment can be nullptr)
+    QList<Cantor::PanelPlugin*> plugins;
+    if (wa)
     {
-        if(plugin==nullptr)
+        QDockWidget* last=nullptr;
+        plugins = m_panelHandler.plugins(wa->session());
+        for(Cantor::PanelPlugin* plugin : plugins)
         {
-            qDebug()<<"somethings wrong";
-            continue;
-        }
-
-        qDebug()<<"adding panel for "<<plugin->name();
-        plugin->setParentWidget(this);
+            if(plugin==nullptr)
+            {
+                qDebug()<<"somethings wrong";
+                continue;
+            }
 
-        QDockWidget* docker=new QDockWidget(plugin->name(), this);
-        docker->setObjectName(plugin->name());
-        docker->setWidget(plugin->widget());
-        addDockWidget ( Qt::RightDockWidgetArea,  docker );
+            qDebug()<<"adding panel for "<<plugin->name();
 
-        // Set visibility for dock from saved info
-        if (isNewWorksheet)
-        {
-            if (plugin->showOnStartup())
-                docker->show();
-            else
-                docker->hide();
-        }
-        else
-        {
-            if (m_pluginsVisibility[m_part].contains(plugin->name()))
-                docker->show();
+            if (m_pluginsStates.contains(m_part))
+                plugin->restoreState(m_pluginsStates[m_part][plugin->name()]);
             else
-                docker->hide();
-        }
+            {
+                Cantor::PanelPlugin::State initState;
+                initState.session = wa->session();
+                plugin->restoreState(initState);
+            }
 
-        if(last!=nullptr)
-            tabifyDockWidget(last, docker);
-        last=docker;
+            QDockWidget* foundDocker = nullptr;
+            for (QDockWidget* docker : m_panels)
+                if (docker->objectName() == plugin->name())
+                {
+                    foundDocker = docker;
+                    break;
+                }
 
-        connect(plugin, &Cantor::PanelPlugin::visibilityRequested, this, &CantorShell::pluginVisibilityRequested);
+            if (!foundDocker)
+            {
+                qDebug() << "something wrong: can't find panel for plugin \"" << plugin->name() << "\"";
+                continue;
+            }
 
-        m_panels.append(docker);
+            // Set visibility for dock from saved info
+            if (isNewWorksheet)
+            {
+                if (plugin->showOnStartup())
+                    foundDocker->show();
+                else
+                    foundDocker->hide();
+            }
+            else
+            {
+                if (m_pluginsVisibility[m_part].contains(plugin->name()))
+                    foundDocker->show();
+                else
+                    foundDocker->hide();
+            }
+
+            if(last!=nullptr)
+                tabifyDockWidget(last, foundDocker);
+            last = foundDocker;
 
-        //Create the action to show/hide this panel
-        panelActions<<docker->toggleViewAction();
+            //Create the action to show/hide this panel
+            panelActions<<foundDocker->toggleViewAction();
 
+        }
+    }
+
+    // Hide plugins, which don't supported on current session
+    QList<Cantor::PanelPlugin*> allPlugins=m_panelHandler.allPlugins();
+    for(Cantor::PanelPlugin* plugin : allPlugins)
+    {
+        if (plugins.indexOf(plugin) == -1)
+            for (QDockWidget* docker : m_panels)
+                if (docker->objectName() == plugin->name())
+                {
+                    docker->hide();
+                    break;
+                }
     }
 
     plugActionList(QLatin1String("view_show_panel_list"), panelActions);
@@ -769,7 +827,7 @@ void CantorShell::pluginVisibilityRequested()
     Cantor::PanelPlugin* plugin = static_cast<Cantor::PanelPlugin*>(sender());
     for (QDockWidget* docker: m_panels)
     {
-        if (plugin->name() == docker->windowTitle())
+        if (plugin->name() == docker->objectName())
         {
             if (docker->isHidden())
                 docker->show();
@@ -829,3 +887,11 @@ void CantorShell::updateBackendForPart(const QString& backend)
         }
     }
 }
+
+void CantorShell::pluginCommandRunRequested(const QString& cmd)
+{
+    if (m_part)
+    {
+        QMetaObject::invokeMethod(m_part, "runCommand", Qt::QueuedConnection, Q_ARG(QString, cmd));
+    }
+}
diff --git a/src/cantor.h b/src/cantor.h
index b32fc5826ff745b46eca4c3ccac91e986e685075..2c1196722183bc6c8f99eaf199540d32953e733f 100644
--- a/src/cantor.h
+++ b/src/cantor.h
@@ -28,6 +28,9 @@
 #include <QStringList>
 #include <QMap>
 
+#include "lib/panelpluginhandler.h"
+#include "lib/panelplugin.h"
+
 class QTabWidget;
 class KTextEdit;
 class KRecentFilesAction;
@@ -40,6 +43,8 @@ namespace KParts{
     class ReadWritePart;
 }
 
+using PanelStates = QMap<QString, Cantor::PanelPlugin::State>;
+
 /**
  * This is the application "Shell".  It has a menubar, toolbar, and
  * statusbar but relies on the "Part" to do all the real work.
@@ -75,6 +80,9 @@ protected:
      */
     void readProperties(const KConfigGroup &) override;
 
+Q_SIGNALS:
+    void showHelp(QString);
+
 public Q_SLOTS:
     void addWorksheet(const QString& backendName);
     /// Use this method/slot to load whatever file/URL you have
@@ -97,10 +105,12 @@ private Q_SLOTS:
     void downloadExamples();
     void openExample();
 
+    void initPanels();
     void updatePanel();
     void updateNewSubmenu();
 
     void pluginVisibilityRequested();
+    void pluginCommandRunRequested(const QString& cmd);
 
 private:
     void setupActions();
@@ -113,6 +123,7 @@ private:
 
 private:
     QMap<KParts::ReadWritePart*, QStringList> m_pluginsVisibility;
+    QMap<KParts::ReadWritePart*, PanelStates> m_pluginsStates;
     QList<KParts::ReadWritePart *> m_parts;
     QMap<KParts::ReadWritePart*, QString> m_parts2Backends;
     KParts::ReadWritePart* m_part;
@@ -122,6 +133,8 @@ private:
     QDockWidget* m_helpDocker;
     KRecentFilesAction* m_recentProjectsAction;
 
+    Cantor::PanelPluginHandler m_panelHandler;
+
     // For better UX: set previous used filter in "Open" action as default filter
     QString m_previousFilter;
 };
diff --git a/src/cantor_part.cpp b/src/cantor_part.cpp
index 3348b3f6df071acd4b3af93ce50eb331b9b4ca1e..f011d7acfbf0623ea84023728501ca41d08c9db9 100644
--- a/src/cantor_part.cpp
+++ b/src/cantor_part.cpp
@@ -110,7 +110,6 @@ class WorksheetAccessInterfaceImpl : public Cantor::WorksheetAccessInterface
 
 CantorPart::CantorPart( QWidget *parentWidget, QObject *parent, const QVariantList & args ): KParts::ReadWritePart(parent),
     m_searchBar(nullptr),
-    m_panelHandler(new Cantor::PanelPluginHandler(this)),
     m_initProgressDlg(nullptr),
     m_showProgressDlg(true),
     m_currectZoomAction(nullptr),
@@ -118,8 +117,6 @@ CantorPart::CantorPart( QWidget *parentWidget, QObject *parent, const QVariantLi
     m_statusBarBlocked(false),
     m_sessionStatusCounter(0)
 {
-    connect(m_panelHandler, &Cantor::PanelPluginHandler::pluginsChanged, this, &CantorPart::pluginsChanged);
-
     QString backendName;
     if(!args.isEmpty())
         backendName = args.first().toString();
@@ -693,7 +690,6 @@ void CantorPart::initialized()
         connect(m_worksheet->session(), &Cantor::Session::error, this, &CantorPart::showSessionError);
 
         loadAssistants();
-        m_panelHandler->setSession(m_worksheet->session());
         adjustGuiToSession();
 
         // Don't set modification flag, if we add command entry in empty worksheet
@@ -773,12 +769,6 @@ void CantorPart::updateCaption()
         emit setCaption(filename+QLatin1Char(' ') + i18n("[read-only]"), QIcon());
 }
 
-void CantorPart::pluginsChanged()
-{
-    for (auto* plugin : m_panelHandler->plugins())
-        connect(plugin, &Cantor::PanelPlugin::requestRunCommand, this, &CantorPart::runCommand);
-}
-
 void CantorPart::loadAssistants()
 {
     qDebug()<<"loading assistants...";
diff --git a/src/cantor_part.h b/src/cantor_part.h
index cd4b2a57aa90e3f142f14fab5fcc608245bd36fc..e71346316e6fd9aa64a08b7479e262b8bb174612 100644
--- a/src/cantor_part.h
+++ b/src/cantor_part.h
@@ -84,7 +84,6 @@ Q_SIGNALS:
     void setCaption(const QString& caption, const QIcon& icon);
     void showHelp(const QString& help);
     void worksheetSave(const QUrl& url);
-    void requestOpenWorksheet(const QUrl& url);
     void setBackendName(const QString& name);
 
 public Q_SLOTS:
@@ -132,7 +131,6 @@ protected Q_SLOTS:
     void worksheetSessionLoginDone();
     void initialized();
 
-    void pluginsChanged();
     void runCommand(const QString& value);
 
     void runAssistant();
@@ -168,7 +166,6 @@ private:
     WorksheetView *m_worksheetview;
     SearchBar *m_searchBar;
     QPointer<ScriptEditorWidget> m_scriptEditor;
-    Cantor::PanelPluginHandler* m_panelHandler;
 
     QProgressDialog* m_initProgressDlg;
     bool m_showProgressDlg;
diff --git a/src/lib/panelplugin.cpp b/src/lib/panelplugin.cpp
index b7d18263799935b0608008baca6361bc7d7e1cff..9364782e5b97092ef39acd279096a93821c4e307 100644
--- a/src/lib/panelplugin.cpp
+++ b/src/lib/panelplugin.cpp
@@ -75,18 +75,24 @@ QString PanelPlugin::name()
     return d->name;
 }
 
-Session* PanelPlugin::session()
+Cantor::PanelPlugin::State Cantor::PanelPlugin::saveState()
 {
-    return d->session;
+    Cantor::PanelPlugin::State state;
+    state.session = d->session;
+    return state;
 }
 
-void PanelPlugin::setSession(Session* session)
+void Cantor::PanelPlugin::restoreState(const Cantor::PanelPlugin::State& state)
 {
-    d->session=session;
-    onSessionChanged();
+    d->session = state.session;
+}
+
+Cantor::Session * Cantor::PanelPlugin::session()
+{
+    return d->session;
 }
 
-void PanelPlugin::onSessionChanged()
+void Cantor::PanelPlugin::connectToShell(QObject* /* cantorShell */)
 {
 
 }
diff --git a/src/lib/panelplugin.h b/src/lib/panelplugin.h
index 6bd4e06ccf1170451d9759cc54c2270a8e3e0978..4ceb9905ff9c55c5ac2ab401303310d4fbb64034 100644
--- a/src/lib/panelplugin.h
+++ b/src/lib/panelplugin.h
@@ -40,6 +40,12 @@ class CANTOR_EXPORT PanelPlugin : public QObject
 {
   Q_OBJECT
   public:
+    struct State {
+        Session* session{nullptr};
+        QVector<QVariant> inners;
+    };
+
+
     /**
      * Create a new PanelPlugin
      * @param parent the parent Object @see QObject
@@ -91,14 +97,21 @@ class CANTOR_EXPORT PanelPlugin : public QObject
     QWidget* parentWidget();
 
     /**
-     * sets the session this plugin operates on
+     * Save state of panel to storable form
+     *
      **/
-    void setSession(Session* session);
+    virtual State saveState();
 
     /**
-     * returns the session
+     * Restore state
+     * Can contains only session - this is init state from Cantor shell
      */
-    Session* session();
+    virtual void restoreState(const State& state);
+
+    /**
+     * For proper connection to Cantor shell. All connections should be done here
+     */
+    virtual void connectToShell(QObject* cantorShell);
 
     /**
      * Show on worksheet startup or not
@@ -106,13 +119,13 @@ class CANTOR_EXPORT PanelPlugin : public QObject
      */
     virtual bool showOnStartup();
 
+  protected:
+    Session* session();
+
   Q_SIGNALS:
     void requestRunCommand(const QString& cmd);
     void visibilityRequested();
 
-  protected:
-    virtual void onSessionChanged();
-
   private:
     PanelPluginPrivate* d;
 };
diff --git a/src/lib/panelpluginhandler.cpp b/src/lib/panelpluginhandler.cpp
index a4f0878eaecd60baa62c6732d1f0421dd01fc37b..394f5a5427ee73edcf839dc99477de9e9c01d68c 100644
--- a/src/lib/panelpluginhandler.cpp
+++ b/src/lib/panelpluginhandler.cpp
@@ -35,14 +35,12 @@ class Cantor::PanelPluginHandlerPrivate
 {
   public:
     QList<Cantor::PanelPlugin*> plugins;
-    Cantor::Session* session;
 };
 
 PanelPluginHandler::PanelPluginHandler( QObject* parent ) : QObject(parent) ,
                                                             d(new PanelPluginHandlerPrivate)
 {
     setObjectName(QStringLiteral("PanelPluginHandler"));
-    d->session=nullptr;
 }
 
 PanelPluginHandler::~PanelPluginHandler()
@@ -52,34 +50,28 @@ PanelPluginHandler::~PanelPluginHandler()
 
 void PanelPluginHandler::loadPlugins()
 {
-    if(d->session==nullptr)
-        return;
-    qDebug()<<"loading panel plugins for session of type "<<d->session->backend()->name();
-
     QStringList panelDirs;
-    foreach(const QString &dir, QCoreApplication::libraryPaths()){
+    foreach(const QString &dir, QCoreApplication::libraryPaths()) {
         panelDirs << dir + QDir::separator() + QLatin1String("cantor/panels");
     }
 
     QPluginLoader loader;
-    const Cantor::Backend::Capabilities capabilities = d->session->backend()->capabilities();
-    const QStringList& extensions = d->session->backend()->extensions();
     foreach(const QString &dir, panelDirs){
-
         qDebug() << "dir: " << dir;
         QStringList panels;
         QDir panelDir = QDir(dir);
 
         panels = panelDir.entryList();
 
-        foreach (const QString &panel, panels){
+        foreach (const QString &panel, panels)
+        {
             if (panel==QLatin1String(".") || panel==QLatin1String(".."))
                 continue;
 
             loader.setFileName(dir + QDir::separator() + panel);
 
             if (!loader.load()){
-                qDebug() << "Error while loading panel: " << panel;
+                qDebug() << "Error while loading panel" << panel << ": \"" << loader.errorString() << "\"";
                 continue;
             }
 
@@ -89,47 +81,50 @@ void PanelPluginHandler::loadPlugins()
             KPluginMetaData info(loader);
             plugin->setPluginInfo(info);
 
-            bool supported=true;
-            foreach(const QString& req, plugin->requiredExtensions()){
-                // FIXME: That req.isEmpty() is there just because Help Panel has req
-                // empty, returning FALSE when the comparison must to return TRUE.
-                supported = supported && (extensions.contains(req) || req.isEmpty());
-            }
+            // This set session to null inside plugin
+            Cantor::PanelPlugin::State emptyState;
+            plugin->restoreState(emptyState);
 
-            supported = supported && ( (capabilities & plugin->requiredCapabilities()) == plugin->requiredCapabilities());
-
-            if(supported)
-            {
-                qDebug() << "plugin " << info.name()<<" is supported, requires extensions " << plugin->requiredExtensions();
-                d->plugins.append(plugin);
-                plugin->setSession(d->session);
-            }else
-            {
-                qDebug() << "plugin " << info.name() <<" is not supported";
-                plugin->deleteLater();
-            }
+            d->plugins.append(plugin);
         }
     }
-
-    emit pluginsChanged();
-}
-
-void PanelPluginHandler::setSession(Session* session)
-{
-    qDeleteAll(d->plugins);
-    d->plugins.clear();
-    d->session=session;
-    loadPlugins();
 }
 
-QList<PanelPlugin*> PanelPluginHandler::plugins()
+QList<Cantor::PanelPlugin *> Cantor::PanelPluginHandler::allPlugins()
 {
     return d->plugins;
 }
 
-void PanelPluginHandler::addPlugin(PanelPlugin* plugin)
+QList<PanelPlugin*> PanelPluginHandler::plugins(Session* session)
 {
-    d->plugins.append(plugin);
-}
+    QList<PanelPlugin*> pluginsForSession;
+
+    if (session == nullptr)
+        return pluginsForSession;
+
+    const Cantor::Backend::Capabilities capabilities = session->backend()->capabilities();
+    const QStringList& extensions = session->backend()->extensions();
+
+    qDebug()<<"loading panel plugins for session of type "<<session->backend()->name();
+    for(Cantor::PanelPlugin* plugin : d->plugins)
+    {
+        bool supported=true;
+        foreach(const QString& req, plugin->requiredExtensions()){
+            // FIXME: That req.isEmpty() is there just because Help Panel has req
+            // empty, returning FALSE when the comparison must to return TRUE.
+            supported = supported && (extensions.contains(req) || req.isEmpty());
+        }
 
+        supported = supported && ( (capabilities & plugin->requiredCapabilities()) == plugin->requiredCapabilities());
 
+        if(supported)
+        {
+            qDebug() << "plugin " << plugin->name()<<" is supported, requires extensions " << plugin->requiredExtensions();
+            pluginsForSession.append(plugin);
+        }
+        else
+            qDebug() << "plugin " << plugin->name() <<" is not supported";
+    }
+
+    return pluginsForSession;
+}
diff --git a/src/lib/panelpluginhandler.h b/src/lib/panelpluginhandler.h
index db66b30650228b168799ab7073747327f8308892..f3930961cec5eb3f257232ec959b7b7e575fca42 100644
--- a/src/lib/panelpluginhandler.h
+++ b/src/lib/panelpluginhandler.h
@@ -32,8 +32,7 @@ class Session;
 
 /**
  * Simple interface that exports a list of known PanelPlugins.
- * Needed as the Panel must be handled by the Shell while plugins
- * belong to the Part.
+ * Needed as the Panel must be handled by the Shell
  */
 
 class CANTOR_EXPORT PanelPluginHandler : public QObject
@@ -43,16 +42,9 @@ class CANTOR_EXPORT PanelPluginHandler : public QObject
     explicit PanelPluginHandler(QObject* parent);
     ~PanelPluginHandler() override;
 
-    QList<PanelPlugin*> plugins();
+    QList<PanelPlugin*> allPlugins();
+    QList<PanelPlugin*> plugins(Session* session);
 
-    void addPlugin(PanelPlugin* plugin);
-
-    void setSession(Session* session);
-
-  Q_SIGNALS:
-    void pluginsChanged();
-
-  private:
     void loadPlugins();
 
   private:
diff --git a/src/panelplugins/filebrowserpanel/filebrowserpanelplugin.cpp b/src/panelplugins/filebrowserpanel/filebrowserpanelplugin.cpp
index 6e968dc918d50b1ef215f8bc351477d24b8570d4..93fb478b91a2a3360c4accf34e1b17adae8b9eba 100644
--- a/src/panelplugins/filebrowserpanel/filebrowserpanelplugin.cpp
+++ b/src/panelplugins/filebrowserpanel/filebrowserpanelplugin.cpp
@@ -74,12 +74,17 @@ QWidget* FileBrowserPanelPlugin::widget()
 
         constructMainWidget();
 
-        connect(this, SIGNAL(requestOpenWorksheet(QUrl)), parent()->parent(), SIGNAL(requestOpenWorksheet(QUrl)));
+
     }
 
     return m_mainWidget;
 }
 
+void FileBrowserPanelPlugin::connectToShell(QObject* cantorShell)
+{
+    connect(this, SIGNAL(requestOpenWorksheet(QUrl)), cantorShell, SLOT(load(QUrl)));
+}
+
 bool FileBrowserPanelPlugin::showOnStartup()
 {
     return false;
diff --git a/src/panelplugins/filebrowserpanel/filebrowserpanelplugin.h b/src/panelplugins/filebrowserpanel/filebrowserpanelplugin.h
index 460652b71572b9255dc7829b4867440894111411..78396c745942834b0ee80814128776f861786b3e 100644
--- a/src/panelplugins/filebrowserpanel/filebrowserpanelplugin.h
+++ b/src/panelplugins/filebrowserpanel/filebrowserpanelplugin.h
@@ -44,6 +44,10 @@ class FileBrowserPanelPlugin : public Cantor::PanelPlugin
 
     bool showOnStartup() override;
 
+    void connectToShell(QObject * cantorShell) override;
+
+    // No use restore files, because the FileBrowser Panel can be shared between session
+
   Q_SIGNALS:
     void requestOpenWorksheet(const QUrl&);
 
diff --git a/src/panelplugins/helppanel/helppanelplugin.cpp b/src/panelplugins/helppanel/helppanelplugin.cpp
index 3a493fd7246cb3e640fe99cc577dedcf1bf92fb4..82f7b94885c77a1e39b86788eb31094dba0540bd 100644
--- a/src/panelplugins/helppanel/helppanelplugin.cpp
+++ b/src/panelplugins/helppanel/helppanelplugin.cpp
@@ -40,10 +40,6 @@ QWidget* HelpPanelPlugin::widget()
         m_edit = new KTextEdit(parentWidget());
         setHelpHtml(i18n("<h1>Cantor</h1>The KDE way to do Mathematics"));
         m_edit->setTextInteractionFlags(Qt::TextBrowserInteraction);
-
-        //using old-style syntax here, otherwise we'd need to include and link to CantorPart and KParts
-        connect(parent()->parent(), SIGNAL(showHelp(QString)), this, SLOT(setHelpHtml(QString)));
-        connect(parent()->parent(), SIGNAL(showHelp(QString)), this, SIGNAL(visibilityRequested()));
     }
 
     return m_edit;
@@ -71,5 +67,29 @@ bool HelpPanelPlugin::showOnStartup()
     return false;
 }
 
+void HelpPanelPlugin::connectToShell(QObject* cantorShell)
+{
+    //using old-style syntax here, otherwise we'd need to include and link to CantorPart and KParts
+    connect(cantorShell, SIGNAL(showHelp(QString)), this, SLOT(setHelpHtml(QString)));
+    connect(cantorShell, SIGNAL(showHelp(QString)), this, SIGNAL(visibilityRequested()));
+}
+
+Cantor::PanelPlugin::State HelpPanelPlugin::saveState()
+{
+    Cantor::PanelPlugin::State state = PanelPlugin::saveState();
+    state.inners.append(m_edit->toHtml());
+    return state;
+}
+
+void HelpPanelPlugin::restoreState(const Cantor::PanelPlugin::State& state)
+{
+    PanelPlugin::restoreState(state);
+    if(state.inners.size() > 0)
+        setHelpHtml(state.inners.first().toString());
+    else
+        setHelpHtml(i18n("<h1>Cantor</h1>The KDE way to do Mathematics"));
+}
+
+
 K_PLUGIN_FACTORY_WITH_JSON(helppanelplugin, "helppanelplugin.json", registerPlugin<HelpPanelPlugin>();)
 #include "helppanelplugin.moc"
diff --git a/src/panelplugins/helppanel/helppanelplugin.h b/src/panelplugins/helppanel/helppanelplugin.h
index 736b0fb606f04cc717023daa8f8888e6c6b0f93e..6a0152f1a8a2e12811c70bcba3753a4ba53f616d 100644
--- a/src/panelplugins/helppanel/helppanelplugin.h
+++ b/src/panelplugins/helppanel/helppanelplugin.h
@@ -36,6 +36,12 @@ class HelpPanelPlugin : public Cantor::PanelPlugin
 
     bool showOnStartup() override;
 
+    void connectToShell(QObject * cantorShell) override;
+
+    Cantor::PanelPlugin::State saveState() override;
+
+    void restoreState(const Cantor::PanelPlugin::State & state) override;
+
   public Q_SLOTS:
     void setHelpHtml(const QString&);
     void showHelp(const QString&);
diff --git a/src/panelplugins/variablemgr/variablemanagerplugin.cpp b/src/panelplugins/variablemgr/variablemanagerplugin.cpp
index ea32ee07617f5222e5976a423b34f43b3c88e0c7..5f42f21508c1169d873e15aa5c69558d4562ad2f 100644
--- a/src/panelplugins/variablemgr/variablemanagerplugin.cpp
+++ b/src/panelplugins/variablemgr/variablemanagerplugin.cpp
@@ -33,8 +33,9 @@ VariableManagerPlugin::~VariableManagerPlugin()
     delete m_widget;
 }
 
-void VariableManagerPlugin::onSessionChanged()
+void VariableManagerPlugin::restoreState(const Cantor::PanelPlugin::State& state)
 {
+    PanelPlugin::restoreState(state);
     if(m_widget)
         m_widget->setSession(session());
 }
diff --git a/src/panelplugins/variablemgr/variablemanagerplugin.h b/src/panelplugins/variablemgr/variablemanagerplugin.h
index 20fc25eb8f8773c08f3c4af1e94c951012c791fb..44a8cfdf73515078e5f22243b1e52da2a8ca0bb8 100644
--- a/src/panelplugins/variablemgr/variablemanagerplugin.h
+++ b/src/panelplugins/variablemgr/variablemanagerplugin.h
@@ -36,9 +36,7 @@ class VariableManagerPlugin : public Cantor::PanelPlugin
 
     Cantor::Backend::Capabilities requiredCapabilities() override;
 
-  protected:
-    void onSessionChanged() override;
-
+    void restoreState(const Cantor::PanelPlugin::State & state) override;
 
   private:
     QPointer<VariableManagerWidget> m_widget;
diff --git a/src/panelplugins/variablemgr/variablemanagerwidget.cpp b/src/panelplugins/variablemgr/variablemanagerwidget.cpp
index 9fb8bb4510894b266b0ab1b79f751dd831a85026..46b753f117c8e79c0e222fa0186f8f0238d6a5d8 100644
--- a/src/panelplugins/variablemgr/variablemanagerwidget.cpp
+++ b/src/panelplugins/variablemgr/variablemanagerwidget.cpp
@@ -48,28 +48,28 @@ m_table(new QTreeView(this))
     QHBoxLayout* btnLayout=new QHBoxLayout();
     int size=KIconLoader::global()->currentSize(KIconLoader::MainToolbar);
 
-    QToolButton* m_newBtn=new QToolButton(this);
+    m_newBtn=new QToolButton(this);
     m_newBtn->setIcon(QIcon::fromTheme(QLatin1String("document-new")));
     m_newBtn->setToolTip(i18n("Add new variable"));
     m_newBtn->setIconSize(QSize(size, size));
     connect(m_newBtn, &QToolButton::clicked, this, &VariableManagerWidget::newVariable);
     btnLayout->addWidget(m_newBtn);
 
-    QToolButton* m_loadBtn=new QToolButton(this);
+    m_loadBtn=new QToolButton(this);
     m_loadBtn->setIcon(QIcon::fromTheme(QLatin1String("document-open")));
     m_loadBtn->setToolTip(i18n("Load Variables"));
     m_loadBtn->setIconSize(QSize(size, size));
     connect(m_loadBtn, &QToolButton::clicked, this, &VariableManagerWidget::load);
     btnLayout->addWidget(m_loadBtn);
 
-    QToolButton* m_saveBtn=new QToolButton(this);
+    m_saveBtn=new QToolButton(this);
     m_saveBtn->setIcon(QIcon::fromTheme(QLatin1String("document-save")));
     m_saveBtn->setToolTip(i18n("Store Variables"));
     m_saveBtn->setIconSize(QSize(size, size));
     connect(m_saveBtn, &QToolButton::clicked, this, &VariableManagerWidget::save);
     btnLayout->addWidget(m_saveBtn);
 
-    QToolButton* m_clearBtn=new QToolButton(this);
+    m_clearBtn=new QToolButton(this);
     m_clearBtn->setIcon(QIcon::fromTheme(QLatin1String("edit-clear")));
     m_clearBtn->setToolTip(i18n("Clear Variables"));
     m_clearBtn->setIconSize(QSize(size, size));
@@ -79,31 +79,32 @@ m_table(new QTreeView(this))
     layout->addLayout(btnLayout);
 
     setSession(session);
-
-    //check for the methods the backend actually supports, and disable the buttons accordingly
-    Cantor::VariableManagementExtension* ext=
-        dynamic_cast<Cantor::VariableManagementExtension*>(m_session->backend()->extension(QLatin1String("VariableManagementExtension")));
-    if (ext)
-    {
-        if(ext->loadVariables(QString()).isNull())
-            m_loadBtn->setDisabled(true);
-        if(ext->saveVariables(QString()).isNull())
-            m_saveBtn->setDisabled(true);
-        if(ext->addVariable(QString(), QString()).isNull())
-            m_newBtn->setDisabled(true);
-        if(ext->clearVariables().isNull())
-            m_clearBtn->setDisabled(true);
-    }
 }
 
 void VariableManagerWidget::setSession(Cantor::Session* session)
 {
-    m_session=session;
+    m_session = session;
     if(session)
     {
         m_model=session->variableDataModel();
         if(m_table)
             m_table->setModel(m_model);
+
+        //check for the methods the backend actually supports, and disable the buttons accordingly
+        Cantor::VariableManagementExtension* ext = dynamic_cast<Cantor::VariableManagementExtension*>(
+            m_session->backend()->extension(QLatin1String("VariableManagementExtension"))
+        );
+        if (ext)
+        {
+            if(ext->loadVariables(QString()).isNull())
+                m_loadBtn->setDisabled(true);
+            if(ext->saveVariables(QString()).isNull())
+                m_saveBtn->setDisabled(true);
+            if(ext->addVariable(QString(), QString()).isNull())
+                m_newBtn->setDisabled(true);
+            if(ext->clearVariables().isNull())
+                m_clearBtn->setDisabled(true);
+        }
     }
 }
 
diff --git a/src/panelplugins/variablemgr/variablemanagerwidget.h b/src/panelplugins/variablemgr/variablemanagerwidget.h
index 45fe27e4a32ce51adafa8d47bc5499f479778f31..0b9bcc2f01d58dc747fac3f6c0f599cb2d282f35 100644
--- a/src/panelplugins/variablemgr/variablemanagerwidget.h
+++ b/src/panelplugins/variablemgr/variablemanagerwidget.h
@@ -28,6 +28,7 @@ class Session;
 }
 
 class QTreeView;
+class QToolButton;
 class QAbstractItemModel;
 
 class VariableManagerWidget : public QWidget
@@ -53,6 +54,10 @@ class VariableManagerWidget : public QWidget
     Cantor::Session* m_session;
     QAbstractItemModel* m_model;
     QTreeView* m_table;
+    QToolButton* m_newBtn;
+    QToolButton* m_loadBtn;
+    QToolButton* m_saveBtn;
+    QToolButton* m_clearBtn;
 };
 
 #endif /* _VARIABLEMANAGERWIDGET_H */