NotebookExplorer: support separated node explorer

src/core/configmgr.cpp

@@ -25,7 +25,7 @@
 using namespace vnotex;
 
 #ifndef QT_NO_DEBUG
-    #define VX_DEBUG_WEB
+    // #define VX_DEBUG_WEB
 #endif
 
 const QString ConfigMgr::c_orgName = "VNote";

src/core/mainconfig.cpp

@@ -119,5 +119,7 @@ QString MainConfig::getVersion(const QJsonObject &p_jobj)
 void MainConfig::doVersionSpecificOverride()
 {
     // In a new version, we may want to change one value by force.
+    // For 3.12.0.
     m_editorConfig->getTextEditorConfig().m_highlightWhitespace = false;
+    m_editorConfig->getMarkdownEditorConfig().m_imageAlignCenterEnabled = false;
 }

src/core/markdowneditorconfig.h

@@ -211,7 +211,7 @@ namespace vnotex
         // Whether enable image width constraint.
         bool m_constrainImageWidthEnabled = true;
 
-        bool m_imageAlignCenterEnabled = true;
+        bool m_imageAlignCenterEnabled = false;
 
         // Whether enable in-place preview width constraint.
         bool m_constrainInplacePreviewWidthEnabled = false;

src/core/sessionconfig.cpp

@@ -222,6 +222,7 @@ QJsonObject SessionConfig::saveStateAndGeometry() const
     writeByteArray(obj, QStringLiteral("main_window_geometry"), m_mainWindowStateGeometry.m_mainGeometry);
     writeStringList(obj, QStringLiteral("visible_docks_before_expand"), m_mainWindowStateGeometry.m_visibleDocksBeforeExpand);
     writeByteArray(obj, QStringLiteral("tag_explorer_state"), m_mainWindowStateGeometry.m_tagExplorerState);
+    writeByteArray(obj, QStringLiteral("notebook_explorer_state"), m_mainWindowStateGeometry.m_notebookExplorerState);
     return obj;
 }
 
@@ -353,6 +354,7 @@ void SessionConfig::loadStateAndGeometry(const QJsonObject &p_session)
     m_mainWindowStateGeometry.m_mainGeometry = readByteArray(obj, QStringLiteral("main_window_geometry"));
     m_mainWindowStateGeometry.m_visibleDocksBeforeExpand = readStringList(obj, QStringLiteral("visible_docks_before_expand"));
     m_mainWindowStateGeometry.m_tagExplorerState = readByteArray(obj, QStringLiteral("tag_explorer_state"));
+    m_mainWindowStateGeometry.m_notebookExplorerState = readByteArray(obj, QStringLiteral("notebook_explorer_state"));
 }
 
 QByteArray SessionConfig::getViewAreaSessionAndClear()

src/core/sessionconfig.h

@@ -37,7 +37,8 @@ namespace vnotex
                 return m_mainState == p_other.m_mainState
                        && m_mainGeometry == p_other.m_mainGeometry
                        && m_visibleDocksBeforeExpand == p_other.m_visibleDocksBeforeExpand
-                       && m_tagExplorerState == p_other.m_tagExplorerState;
+                       && m_tagExplorerState == p_other.m_tagExplorerState
+                       && m_notebookExplorerState == p_other.m_notebookExplorerState;
             }
 
             QByteArray m_mainState;
@@ -47,6 +48,8 @@ namespace vnotex
             QStringList m_visibleDocksBeforeExpand;
 
             QByteArray m_tagExplorerState;
+
+            QByteArray m_notebookExplorerState;
         };
 
         enum OpenGL

src/core/widgetconfig.cpp

@@ -31,6 +31,7 @@ void WidgetConfig::init(const QJsonObject &p_app,
 
     {
         m_nodeExplorerViewOrder = READINT(QStringLiteral("node_explorer_view_order"));
+        m_nodeExplorerExploreMode = READINT(QStringLiteral("node_explorer_explore_mode"));
         m_nodeExplorerExternalFilesVisible = READBOOL(QStringLiteral("node_explorer_external_files_visible"));
         m_nodeExplorerAutoImportExternalFilesEnabled = READBOOL(QStringLiteral("node_explorer_auto_import_external_files_enabled"));
         m_nodeExplorerCloseBeforeOpenWithEnabled = READBOOL(QStringLiteral("node_explorer_close_before_open_with_enabled"));
@@ -54,6 +55,7 @@ QJsonObject WidgetConfig::toJson() const
     obj[QStringLiteral("find_and_replace_options")] = static_cast<int>(m_findAndReplaceOptions);
 
     obj[QStringLiteral("node_explorer_view_order")] = m_nodeExplorerViewOrder;
+    obj[QStringLiteral("node_explorer_explore_mode")] = m_nodeExplorerExploreMode;
     obj[QStringLiteral("node_explorer_external_files_visible")] = m_nodeExplorerExternalFilesVisible;
     obj[QStringLiteral("node_explorer_auto_import_external_files_enabled")] = m_nodeExplorerAutoImportExternalFilesEnabled;
     obj[QStringLiteral("node_explorer_close_before_open_with_enabled")] = m_nodeExplorerCloseBeforeOpenWithEnabled;
@@ -106,6 +108,16 @@ void WidgetConfig::setNodeExplorerViewOrder(int p_viewOrder)
     updateConfig(m_nodeExplorerViewOrder, p_viewOrder, this);
 }
 
+int WidgetConfig::getNodeExplorerExploreMode() const
+{
+    return m_nodeExplorerExploreMode;
+}
+
+void WidgetConfig::setNodeExplorerExploreMode(int p_mode)
+{
+    updateConfig(m_nodeExplorerExploreMode, p_mode, this);
+}
+
 bool WidgetConfig::isNodeExplorerExternalFilesVisible() const
 {
     return m_nodeExplorerExternalFilesVisible;

src/core/widgetconfig.h

@@ -30,6 +30,9 @@ namespace vnotex
         int getNodeExplorerViewOrder() const;
         void setNodeExplorerViewOrder(int p_viewOrder);
 
+        int getNodeExplorerExploreMode() const;
+        void setNodeExplorerExploreMode(int p_mode);
+
         bool isNodeExplorerExternalFilesVisible() const;
         void setNodeExplorerExternalFilesVisible(bool p_visible);
 
@@ -60,6 +63,8 @@ namespace vnotex
 
         int m_nodeExplorerViewOrder = 0;
 
+        int m_nodeExplorerExploreMode = 1;
+
         bool m_nodeExplorerExternalFilesVisible = true;
 
         bool m_nodeExplorerAutoImportExternalFilesEnabled = true;

src/data/core/vnotex.json

@@ -335,7 +335,7 @@
             "section_number_style" : "digdotdigdot",
             "//comment" : "Whether enable image width constraint",
             "constrain_image_width" : true,
-            "image_align_center" : true,
+            "image_align_center" : false,
             "//comment" : "Whether enable in-place preview width constraint",
             "constrain_inplace_preview_width" : false,
             "//comment" : "Zoom factor in read mode",
@@ -383,12 +383,14 @@
         "outline_section_number_enabled" : false,
         "//comment" : "Default find options in FindAndReplace",
         "find_and_replace_options" : 16,
-        "//comment" : "View order of the node explorer",
+        "//comment" : "View order of the node explorer (NotebookNodeExplorer::ViewOrder)",
         "node_explorer_view_order" : 0,
         "node_explorer_external_files_visible" : true,
         "node_explorer_auto_import_external_files_enabled" : true,
         "//comment" : "Whether close the file before opening it with external program",
         "node_explorer_close_before_open_with_enabled" : true,
+        "//comment" : "0 - combined/1 - separate_single/2 - separate_double",
+        "node_explorer_explore_mode" : 1,
         "search_panel_advanced_settings_visible" : true,
         "//comment" : "Docks to ignore when expanding content area of main window",
         "main_window_keep_docks_expanding_content_area": ["OutlineDock.vnotex"],

src/data/extra/themes/moonlight/text-editor.theme

@@ -30,7 +30,7 @@
         },
         "IndicatorsBorder" : {
             "text-color" : "#8a93a6",
-            "background-color" : "#2d323b"
+            "background-color" : "#3c414d"
         },
         "CurrentLineNumber" : {
             "text-color" : "#ccd1d8"

src/export/exportdata.cpp

@@ -42,6 +42,44 @@ bool ExportHtmlOption::operator==(const ExportHtmlOption &p_other) const
            && m_scrollable == p_other.m_scrollable;
 }
 
+static QJsonObject pageLayoutToJsonObject(const QPageLayout &p_layout)
+{
+    QJsonObject obj;
+    obj["page_size"] = static_cast<int>(p_layout.pageSize().id());
+    obj["orientation"] = static_cast<int>(p_layout.orientation());
+    obj["units"] = static_cast<int>(p_layout.units());
+    {
+        QStringList marginsStr;
+        const auto margins = p_layout.margins();
+        marginsStr << QString::number(margins.left());
+        marginsStr << QString::number(margins.top());
+        marginsStr << QString::number(margins.right());
+        marginsStr << QString::number(margins.bottom());
+        obj["margins"] = marginsStr.join(QLatin1Char(','));
+    }
+    return obj;
+}
+
+static void jsonObjectToPageLayout(const QJsonObject &p_obj, QPageLayout &p_layout)
+{
+    const int pageSize = p_obj["page_size"].toInt(static_cast<int>(QPageSize::A4));
+    p_layout.setPageSize(QPageSize(static_cast<QPageSize::PageSizeId>(pageSize)));
+
+    const int orientation = p_obj["orientation"].toInt(static_cast<int>(QPageLayout::Portrait));
+    p_layout.setOrientation(static_cast<QPageLayout::Orientation>(orientation));
+
+    const int units = p_obj["units"].toInt(static_cast<int>(QPageLayout::Millimeter));
+    p_layout.setUnits(static_cast<QPageLayout::Unit>(units));
+
+    auto marginsStr = p_obj["margins"].toString().split(QLatin1Char(','));
+    if (marginsStr.size() == 4) {
+        p_layout.setMargins(QMarginsF(marginsStr[0].toDouble(),
+                                      marginsStr[1].toDouble(),
+                                      marginsStr[2].toDouble(),
+                                      marginsStr[3].toDouble()));
+    }
+}
+
 ExportPdfOption::ExportPdfOption()
     : m_layout(new QPageLayout(QPageSize(QPageSize::A4),
                                QPageLayout::Portrait,
@@ -58,6 +96,7 @@ QJsonObject ExportPdfOption::toJson() const
     obj["all_in_one"] = m_allInOne;
     obj["wkhtmltopdf_exe_path"] = m_wkhtmltopdfExePath;
     obj["wkhtmltopdf_args"] = m_wkhtmltopdfArgs;
+    obj["layout"] = pageLayoutToJsonObject(*m_layout);
     return obj;
 }
 
@@ -72,6 +111,7 @@ void ExportPdfOption::fromJson(const QJsonObject &p_obj)
     m_allInOne = p_obj["all_in_one"].toBool();
     m_wkhtmltopdfExePath = p_obj["wkhtmltopdf_exe_path"].toString();
     m_wkhtmltopdfArgs = p_obj["wkhtmltopdf_args"].toString();
+    jsonObjectToPageLayout(p_obj["layout"].toObject(), *m_layout);
 }
 
 bool ExportPdfOption::operator==(const ExportPdfOption &p_other) const

src/fakeaccessible.cpp

@@ -10,6 +10,7 @@ QAccessibleInterface *FakeAccessible::accessibleFactory(const QString &p_classNa
     // Try to fix non-responsible issue caused by Youdao Dict.
     if (p_className.startsWith(QStringLiteral("vnotex::"))
         || p_className.startsWith(QStringLiteral("vte::"))) {
+        // Qt's docs: All interfaces are managed by an internal cache and should not be deleted.
         return new FakeAccessibleInterface(p_obj);
     }
 

src/widgets/mainwindow.cpp

@@ -427,6 +427,7 @@ void MainWindow::saveStateAndGeometry()
     sg.m_mainGeometry = saveGeometry();
     sg.m_visibleDocksBeforeExpand = m_visibleDocksBeforeExpand;
     sg.m_tagExplorerState = m_tagExplorer->saveState();
+    sg.m_notebookExplorerState = m_notebookExplorer->saveState();
 
     auto& sessionConfig = ConfigMgr::getInst().getSessionConfig();
     sessionConfig.setMainWindowStateGeometry(sg);
@@ -457,6 +458,10 @@ void MainWindow::loadStateAndGeometry(bool p_stateOnly)
     if (!sg.m_tagExplorerState.isEmpty()) {
         m_tagExplorer->restoreState(sg.m_tagExplorerState);
     }
+
+    if (!sg.m_notebookExplorerState.isEmpty()) {
+        m_notebookExplorer->restoreState(sg.m_notebookExplorerState);
+    }
 }
 
 void MainWindow::resetStateAndGeometry()

src/widgets/notebookexplorer.cpp

@@ -82,6 +82,7 @@ void NotebookExplorer::setupUI()
     const auto &widgetConfig = ConfigMgr::getInst().getWidgetConfig();
     m_nodeExplorer = new NotebookNodeExplorer(this);
     m_nodeExplorer->setViewOrder(widgetConfig.getNodeExplorerViewOrder());
+    m_nodeExplorer->setExploreMode(widgetConfig.getNodeExplorerExploreMode());
     m_nodeExplorer->setExternalFilesVisible(widgetConfig.isNodeExplorerExternalFilesVisible());
     connect(m_nodeExplorer, &NotebookNodeExplorer::nodeActivated,
             &VNoteX::getInst(), &VNoteX::openNodeRequested);
@@ -113,11 +114,8 @@ TitleBar *NotebookExplorer::setupTitleBar(QWidget *p_parent)
 
     {
         auto viewMenu = WidgetsFactory::createMenu(titleBar);
-        titleBar->addActionButton(QStringLiteral("view.svg"), tr("View"), viewMenu);
-        connect(viewMenu, &QMenu::aboutToShow,
-                this, [this, viewMenu]() {
         setupViewMenu(viewMenu);
-                });
+        titleBar->addActionButton(QStringLiteral("view.svg"), tr("View"), viewMenu);
     }
 
     {
@@ -205,6 +203,8 @@ TitleBar *NotebookExplorer::setupTitleBar(QWidget *p_parent)
         act->setChecked(widgetConfig.getNodeExplorerCloseBeforeOpenWithEnabled());
     }
 
+    setupExploreModeMenu(titleBar);
+
     return titleBar;
 }
 
@@ -383,10 +383,6 @@ const QSharedPointer<Notebook> &NotebookExplorer::currentNotebook() const
 
 void NotebookExplorer::setupViewMenu(QMenu *p_menu)
 {
-    if (!p_menu->isEmpty()) {
-        return;
-    }
-
     auto ag = new QActionGroup(p_menu);
 
     auto act = ag->addAction(tr("View By Configuration"));
@@ -467,6 +463,45 @@ void NotebookExplorer::setupRecycleBinMenu(QMenu *p_menu)
                       });
 }
 
+void NotebookExplorer::setupExploreModeMenu(TitleBar *p_titleBar)
+{
+    auto menu = p_titleBar->addMenuSubMenu(tr("Explore Mode"));
+
+    auto ag = new QActionGroup(menu);
+
+    auto act = ag->addAction(tr("Combined"));
+    act->setCheckable(true);
+    act->setChecked(true);
+    act->setData(NotebookNodeExplorer::ExploreMode::Combined);
+    menu->addAction(act);
+
+    act = ag->addAction(tr("Separate, Single Column"));
+    act->setCheckable(true);
+    act->setChecked(true);
+    act->setData(NotebookNodeExplorer::ExploreMode::SeparateSingle);
+    menu->addAction(act);
+
+    act = ag->addAction(tr("Separate, Double Columns"));
+    act->setCheckable(true);
+    act->setChecked(true);
+    act->setData(NotebookNodeExplorer::ExploreMode::SeparateDouble);
+    menu->addAction(act);
+
+    int mode = ConfigMgr::getInst().getWidgetConfig().getNodeExplorerExploreMode();
+    for (const auto &act : ag->actions()) {
+        if (act->data().toInt() == mode) {
+            act->setChecked(true);
+        }
+    }
+
+    connect(ag, &QActionGroup::triggered,
+            this, [this](QAction *action) {
+                int mode = action->data().toInt();
+                ConfigMgr::getInst().getWidgetConfig().setNodeExplorerExploreMode(mode);
+                m_nodeExplorer->setExploreMode(mode);
+            });
+}
+
 void NotebookExplorer::saveSession()
 {
     updateSession();
@@ -560,3 +595,13 @@ void NotebookExplorer::rebuildDatabase()
         }
     }
 }
+
+QByteArray NotebookExplorer::saveState() const
+{
+    return m_nodeExplorer->saveState();
+}
+
+void NotebookExplorer::restoreState(const QByteArray &p_data)
+{
+    m_nodeExplorer->restoreState(p_data);
+}

src/widgets/notebookexplorer.h

@@ -30,6 +30,10 @@ namespace vnotex
 
         Node *currentExploredNode() const;
 
+        QByteArray saveState() const;
+
+        void restoreState(const QByteArray &p_data);
+
     public slots:
         void newNotebook();
 
@@ -71,6 +75,8 @@ namespace vnotex
 
         void setupRecycleBinMenu(QMenu *p_menu);
 
+        void setupExploreModeMenu(TitleBar *p_titleBar);
+
         void saveSession();
 
         void loadSession();

src/widgets/notebooknodeexplorer.h

@@ -12,8 +12,6 @@
 #include "navigationmodewrapper.h"
 
 class QSplitter;
-class QTreeWidget;
-class QTreeWidgetItem;
 class QMenu;
 
 namespace vnotex
@@ -21,6 +19,7 @@ namespace vnotex
     class Notebook;
     class Node;
     class TreeWidget;
+    class ListWidget;
     struct FileOpenParameters;
     class Event;
     class ExternalNode;
@@ -65,6 +64,8 @@ namespace vnotex
 
             bool matched(const Node *p_node) const;
 
+            bool matched(const QString &p_name) const;
+
             bool isLoaded() const;
 
         private:
@@ -89,22 +90,26 @@ namespace vnotex
             ViewOrderMax
         };
 
+        enum ExploreMode
+        {
+            Combined = 0,
+            SeparateSingle,
+            SeparateDouble,
+            ExploreModeMax
+        };
+
         explicit NotebookNodeExplorer(QWidget *p_parent = nullptr);
 
         void setNotebook(const QSharedPointer<Notebook> &p_notebook);
 
-        Node *getCurrentNode() const;
-
-        // Update the tree of @p_node.
-        // If @p_node is null, update the whole tree.
-        void updateNode(Node *p_node);
-
         void setCurrentNode(Node *p_node);
 
         void reload();
 
         void setViewOrder(int p_order);
 
+        void setExploreMode(int p_mode);
+
         void setExternalFilesVisible(bool p_visible);
 
         void setAutoImportExternalFiles(bool p_enabled);
@@ -113,6 +118,10 @@ namespace vnotex
 
         Node *currentExploredNode() const;
 
+        QByteArray saveState() const;
+
+        void restoreState(const QByteArray &p_data);
+
         static QString generateToolTip(const Node *p_node);
 
     signals:
@@ -156,81 +165,103 @@ namespace vnotex
             Tag
         };
 
+        struct CacheData
+        {
+            void clear();
+
+            QSharedPointer<QTreeWidgetStateCache<Node *>> m_masterStateCache;
+
+            QString m_currentSlaveName;
+        };
+
         void setupUI();
 
         void setupShortcuts();
 
         void setupMasterExplorer(QWidget *p_parent = nullptr);
 
-        void clearExplorer();
+        void setupSlaveExplorer();
 
-        void generateNodeTree();
+        void generateMasterNodeTree();
 
         void loadRootNode(const Node *p_node) const;
 
-        void loadNode(QTreeWidgetItem *p_item, Node *p_node, int p_level) const;
+        void loadMasterNode(QTreeWidgetItem *p_item, Node *p_node, int p_level) const;
 
-        void loadChildren(QTreeWidgetItem *p_item, Node *p_node, int p_level) const;
+        void loadMasterNodeChildren(QTreeWidgetItem *p_item, Node *p_node, int p_level) const;
 
-        void loadItemChildren(QTreeWidgetItem *p_item) const;
+        void loadMasterItemChildren(QTreeWidgetItem *p_item) const;
 
-        void loadNode(QTreeWidgetItem *p_item, const QSharedPointer<ExternalNode> &p_node) const;
+        void loadMasterExternalNode(QTreeWidgetItem *p_item, const QSharedPointer<ExternalNode> &p_node) const;
 
-        void fillTreeItem(QTreeWidgetItem *p_item, Node *p_node, bool p_loaded) const;
+        void fillMasterItem(QTreeWidgetItem *p_item, Node *p_node, bool p_loaded) const;
 
-        void fillTreeItem(QTreeWidgetItem *p_item, const QSharedPointer<ExternalNode> &p_node) const;
+        void fillMasterItem(QTreeWidgetItem *p_item, const QSharedPointer<ExternalNode> &p_node) const;
 
-        const QIcon &getNodeItemIcon(const Node *p_node) const;
+        void fillSlaveItem(QListWidgetItem *p_item, Node *p_node) const;
 
-        const QIcon &getNodeItemIcon(const ExternalNode *p_node) const;
+        void fillSlaveItem(QListWidgetItem *p_item, const QSharedPointer<ExternalNode> &p_node) const;
+
+        const QIcon &getIcon(const Node *p_node) const;
+
+        const QIcon &getIcon(const ExternalNode *p_node) const;
 
         void initNodeIcons() const;
 
-        QTreeWidgetItem *findNode(const Node *p_node) const;
+        QTreeWidgetItem *findMasterNode(const Node *p_node) const;
 
-        QTreeWidgetItem *findNode(QTreeWidgetItem *p_item, const Node *p_node) const;
+        QTreeWidgetItem *findMasterNode(QTreeWidgetItem *p_item, const Node *p_node) const;
 
-        QTreeWidgetItem *findNodeChild(QTreeWidgetItem *p_item, const Node *p_node) const;
+        QTreeWidgetItem *findMasterNodeInDirectChildren(QTreeWidgetItem *p_item, const Node *p_node) const;
 
-        QTreeWidgetItem *findNodeTopLevelItem(QTreeWidget *p_tree, const Node *p_node) const;
+        QTreeWidgetItem *findMasterNodeInTopLevelItems(QTreeWidget *p_tree, const Node *p_node) const;
 
-        void saveNotebookTreeState(bool p_saveCurrentItem = true);
+        QListWidgetItem *findSlaveNode(const Node *p_node) const;
 
-        QSharedPointer<QTreeWidgetStateCache<Node *>> stateCache() const;
+        void cacheState(bool p_saveCurrent);
 
-        void clearStateCache(const Notebook *p_notebook);
+        // Get cache data of current notebook.
+        CacheData &getCache() const;
 
-        void createContextMenuOnRoot(QMenu *p_menu);
+        void clearCache(const Notebook *p_notebook);
 
-        void createContextMenuOnNode(QMenu *p_menu, const Node *p_node);
+        void createMasterContextMenuOnRoot(QMenu *p_menu);
 
-        void createContextMenuOnExternalNode(QMenu *p_menu, const ExternalNode *p_node);
+        void createContextMenuOnNode(QMenu *p_menu, const Node *p_node, bool p_master);
+
+        void createContextMenuOnExternalNode(QMenu *p_menu, const ExternalNode *p_node, bool p_master);
+
+        void createSlaveContextMenuOnMasterNode(QMenu *p_menu);
 
         // Factory function to create action.
-        QAction *createAction(Action p_act, QObject *p_parent);
+        QAction *createAction(Action p_act, QObject *p_parent, bool p_master);
 
-        QAction *createAndAddAction(Action p_act, QMenu *p_menu);
+        QAction *createAndAddAction(Action p_act, QMenu *p_menu, bool p_master = true);
 
-        void copySelectedNodes(bool p_move);
+        void copySelectedNodes(bool p_move, bool p_master);
 
         void pasteNodesFromClipboard();
 
-        QPair<QVector<Node *>, QVector<QSharedPointer<ExternalNode>>> getSelectedNodes() const;
+        QPair<QVector<Node *>, QVector<QSharedPointer<ExternalNode>>> getMasterSelectedNodesAndExternalNodes() const;
 
-        void removeSelectedNodes();
+        QPair<QVector<Node *>, QVector<QSharedPointer<ExternalNode>>> getSlaveSelectedNodesAndExternalNodes() const;
 
-        void removeSelectedNodesFromConfig();
+        void removeSelectedNodes(bool p_master);
+
+        void removeSelectedNodesFromConfig(bool p_master);
 
         QVector<Node *> confirmSelectedNodes(const QString &p_title,
                                              const QString &p_text,
-                                             const QString &p_info) const;
+                                             const QString &p_info,
+                                             bool p_master) const;
 
         static QSharedPointer<ClipboardData> tryFetchClipboardData();
 
         bool isPasteOnNodeAvailable(const Node *p_node) const;
 
-        void setNodeExpanded(const Node *p_node, bool p_expanded);
+        void setMasterNodeExpanded(const Node *p_node, bool p_expanded);
 
+        // Select both master and slave nodes.
         void selectNodes(const QVector<const Node *> &p_nodes);
 
         void removeNodes(QVector<Node *> p_nodes, bool p_configOnly);
@@ -240,19 +271,19 @@ namespace vnotex
         void updateAndExpandNode(Node *p_node);
 
         // Check if all selected items are the same type for operations.
-        bool allSelectedItemsSameType() const;
+        bool isMasterAllSelectedItemsSameType() const;
+
+        bool isSlaveAllSelectedItemsSameType() const;
 
         void focusNormalNode();
 
         void sortNodes(QVector<QSharedPointer<Node>> &p_nodes) const;
 
         // [p_start, p_end).
-        void sortNodes(QVector<QSharedPointer<Node>> &p_nodes, int p_start, int p_end, int p_viewOrder) const;
+        void sortNodes(QVector<QSharedPointer<Node>> &p_nodes, int p_start, int p_end, ViewOrder p_viewOrder) const;
 
         // Sort nodes in config file.
-        void manualSort();
+        void manualSort(bool p_master);
-
-        void openSelectedNodes();
 
         QSharedPointer<Node> importToIndex(QSharedPointer<ExternalNode> p_node);
 
@@ -262,33 +293,67 @@ namespace vnotex
         // Return true if it is invalid.
         bool checkInvalidNode(Node *p_node) const;
 
-        void expandCurrentNodeAll();
+        void addOpenWithMenu(QMenu *p_menu, bool p_master);
 
-        void expandItemRecursively(QTreeWidgetItem *p_item);
+        QStringList getSelectedNodesPath(bool p_master) const;
 
-        void addOpenWithMenu(QMenu *p_menu);
+        void openSelectedNodesWithCommand(const QString &p_command, bool p_master);
 
-        QStringList getSelectedNodesPath() const;
+        bool belongsToMasterExplorer(const Node *p_node) const;
 
-        void openSelectedNodesWithDefaultProgram();
+        bool belongsToMasterExplorer(const ExternalNode *p_node) const;
 
-        void openSelectedNodesWithExternalProgram(const QString &p_command);
+        void updateSlaveExplorer();
+
+        Node *getCurrentMasterNode() const;
+
+        Node *getCurrentSlaveNode() const;
+
+        NodeData getCurrentMasterNodeData() const;
+
+        NodeData getCurrentSlaveNodeData() const;
+
+        Node *getSlaveExplorerMasterNode() const;
+
+        bool isCombinedExploreMode() const;
+
+        // Update the tree of @p_node if there is any. Or update the node itself if it is in slave explorer.
+        // If @p_node is null, update the whole tree.
+        void updateNode(Node *p_node);
+
+        void setCurrentMasterNode(Node *p_node);
+
+        void setCurrentSlaveNode(const Node *p_node);
+
+        void setCurrentSlaveNode(const QString &p_name);
+
+        void activateItemNode(const NodeData &p_data);
 
         static NotebookNodeExplorer::NodeData getItemNodeData(const QTreeWidgetItem *p_item);
 
+        static NotebookNodeExplorer::NodeData getItemNodeData(const QListWidgetItem *p_item);
+
         static void setItemNodeData(QTreeWidgetItem *p_item, const NodeData &p_data);
 
+        static void setItemNodeData(QListWidgetItem *p_item, const NodeData &p_data);
+
         QSplitter *m_splitter = nullptr;
 
         TreeWidget *m_masterExplorer = nullptr;
 
+        ListWidget *m_slaveExplorer = nullptr;
+
         QSharedPointer<Notebook> m_notebook;
 
-        QHash<const Notebook *, QSharedPointer<QTreeWidgetStateCache<Node *>>> m_stateCache;
+        QHash<const Notebook *, CacheData> m_cache;
 
-        QScopedPointer<NavigationModeWrapper<QTreeWidget, QTreeWidgetItem>> m_navigationWrapper;
+        QScopedPointer<NavigationModeWrapper<QTreeWidget, QTreeWidgetItem>> m_masterNavigationWrapper;
 
-        int m_viewOrder = ViewOrder::OrderedByConfiguration;
+        QScopedPointer<NavigationModeWrapper<QListWidget, QListWidgetItem>> m_slaveNavigationWrapper;
+
+        ViewOrder m_viewOrder = ViewOrder::OrderedByConfiguration;
+
+        ExploreMode m_exploreMode = ExploreMode::Combined;
 
         bool m_externalFilesVisible = true;
 

src/widgets/treewidget.cpp

@@ -265,3 +265,20 @@ void TreeWidget::unmark(QTreeWidgetItem *p_item, int p_column)
     p_item->setData(p_column, Qt::ForegroundRole, QVariant());
     p_item->setData(p_column, Qt::BackgroundRole, QVariant());
 }
+
+void TreeWidget::expandRecursively(QTreeWidgetItem *p_item)
+{
+    if (!p_item) {
+        return;
+    }
+
+    p_item->setExpanded(true);
+    const int cnt = p_item->childCount();
+    if (cnt == 0) {
+        return;
+    }
+
+    for (int i = 0; i < cnt; ++i) {
+        expandRecursively(p_item->child(i));
+    }
+}

src/widgets/treewidget.h

@@ -42,6 +42,8 @@ namespace vnotex
         // @p_func: return false to abort the iteration.
         static void forEachItem(const QTreeWidget *p_widget, const std::function<bool(QTreeWidgetItem *p_item)> &p_func);
 
+        static void expandRecursively(QTreeWidgetItem *p_item);
+
     signals:
         // Emit when single item is selected and Drag&Drop to move internally.
         void itemMoved(QTreeWidgetItem *p_item);