Squashed commit of the following:

commit 60c0f65c5e3c2faf1f7b0ae10b4131dabbcf715b
Author: itsmattkc <34096995+itsmattkc@users.noreply.github.com>
Date:   Wed Feb 15 22:34:16 2023 -0800

    mainwindow: don't close last timeline panel when removing sequence

commit bc892810d67c1dd4f9c0639767c563681f29701d
Merge: 69051a120 aef08f8cd
Author: itsmattkc <34096995+itsmattkc@users.noreply.github.com>
Date:   Tue Feb 14 17:05:25 2023 -0800

    Merge branch 'master' into kddockwidgets

commit 69051a120b8423d0ad7b38def2f7555d323cd74d
Author: itsmattkc <34096995+itsmattkc@users.noreply.github.com>
Date:   Tue Feb 14 15:29:24 2023 -0800

    finished kddockwidgets integration

commit 9a39dbeade871a0b9454b424c7f7a7482671d40b
Author: itsmattkc <34096995+itsmattkc@users.noreply.github.com>
Date:   Tue Feb 14 11:54:25 2023 -0800

    switch to kddockwidgets

CMakeLists.txt

@@ -150,8 +150,18 @@ if (${QT_VERSION_MAJOR} EQUAL "6")
   list(APPEND OLIVE_LIBRARIES
     Qt${QT_VERSION_MAJOR}::OpenGLWidgets
   )
+
+  # Link KDDockWidgets
+  find_package(KDDockWidgets-qt6 CONFIG REQUIRED)
+else()
+  # Link KDDockWidgets
+  find_package(KDDockWidgets CONFIG REQUIRED)
 endif()
 
+list(APPEND OLIVE_LIBRARIES
+  KDAB::kddockwidgets
+)
+
 # Link FFmpeg
 find_package(FFMPEG 3.0 REQUIRED
   COMPONENTS

app/core.cpp

@@ -752,6 +752,15 @@ void Core::StartGUI(bool full_screen)
           PanelManager::instance(),
           &PanelManager::FocusChanged);
 
+  // Set KDDockWidgets flags
+  auto &config = KDDockWidgets::Config::self();
+  auto flags = config.flags();
+  flags |= KDDockWidgets::Config::Flag_TabsHaveCloseButton;
+  flags |= KDDockWidgets::Config::Flag_HideTitleBarWhenTabsVisible;
+  flags |= KDDockWidgets::Config::Flag_AlwaysShowTabs;
+  flags |= KDDockWidgets::Config::Flag_AllowReorderTabs;
+  config.setFlags(flags);
+
   // Create main window and open it
   main_window_ = new MainWindow();
 

app/panel/audiomonitor/audiomonitor.cpp

@@ -26,10 +26,10 @@ namespace olive {
 
 #define super PanelWidget
 
-AudioMonitorPanel::AudioMonitorPanel(QWidget *parent) :
-  super(QStringLiteral("AudioMonitor"), parent)
+AudioMonitorPanel::AudioMonitorPanel() :
+  super(QStringLiteral("AudioMonitor"))
 {
-  audio_monitor_ = new AudioMonitor();
+  audio_monitor_ = new AudioMonitor(this);
 
   SetWidgetWithPadding(audio_monitor_);
 

app/panel/audiomonitor/audiomonitor.h

@@ -33,7 +33,7 @@ class AudioMonitorPanel : public PanelWidget
 {
   Q_OBJECT
 public:
-  AudioMonitorPanel(QWidget* parent = nullptr);
+  AudioMonitorPanel();
 
   bool IsPlaying() const
   {

app/panel/curve/curve.cpp

@@ -22,11 +22,11 @@
 
 namespace olive {
 
-CurvePanel::CurvePanel(QWidget *parent) :
-  TimeBasedPanel(QStringLiteral("CurvePanel"), parent)
+CurvePanel::CurvePanel() :
+  TimeBasedPanel(QStringLiteral("CurvePanel"))
 {
   // Create main widget and set it
-  SetTimeBasedWidget(new CurveWidget());
+  SetTimeBasedWidget(new CurveWidget(this));
 
   // Set strings
   Retranslate();

app/panel/curve/curve.h

@@ -30,7 +30,7 @@ class CurvePanel : public TimeBasedPanel
 {
   Q_OBJECT
 public:
-  CurvePanel(QWidget* parent);
+  CurvePanel();
 
   virtual void DeleteSelected() override;
 

app/panel/footageviewer/footageviewer.cpp

@@ -24,11 +24,11 @@ namespace olive {
 
 #define super ViewerPanelBase
 
-FootageViewerPanel::FootageViewerPanel(QWidget *parent) :
-  super(QStringLiteral("FootageViewerPanel"), parent)
+FootageViewerPanel::FootageViewerPanel() :
+  super(QStringLiteral("FootageViewerPanel"))
 {
   // Set ViewerWidget as the central widget
-  FootageViewerWidget* fvw = new FootageViewerWidget();
+  FootageViewerWidget* fvw = new FootageViewerWidget(this);
   SetViewerWidget(fvw);
 
   // Set strings

app/panel/footageviewer/footageviewer.h

@@ -35,7 +35,7 @@ namespace olive {
 class FootageViewerPanel : public ViewerPanelBase, public FootageManagementPanel {
   Q_OBJECT
 public:
-  FootageViewerPanel(QWidget* parent);
+  FootageViewerPanel();
 
   void OverrideWorkArea(const TimeRange &r);
 

app/panel/multicam/multicampanel.cpp

@@ -4,10 +4,10 @@ namespace olive {
 
 #define super TimeBasedPanel
 
-MulticamPanel::MulticamPanel(QWidget *parent) :
-  super(QStringLiteral("MultiCamPanel"), parent)
+MulticamPanel::MulticamPanel() :
+  super(QStringLiteral("MultiCamPanel"))
 {
-  SetTimeBasedWidget(new MulticamWidget());
+  SetTimeBasedWidget(new MulticamWidget(this));
 
   Retranslate();
 }

app/panel/multicam/multicampanel.h

@@ -10,7 +10,7 @@ class MulticamPanel : public TimeBasedPanel
 {
   Q_OBJECT
 public:
-  MulticamPanel(QWidget* parent = nullptr);
+  MulticamPanel();
 
   MulticamWidget *GetMulticamWidget() const { return static_cast<MulticamWidget *>(GetTimeBasedWidget()); }
 

app/panel/node/node.cpp

@@ -22,11 +22,11 @@
 
 namespace olive {
 
-NodePanel::NodePanel(QWidget *parent) :
-  PanelWidget(QStringLiteral("NodePanel"), parent)
+NodePanel::NodePanel() :
+  PanelWidget(QStringLiteral("NodePanel"))
 {
-  node_widget_ = new NodeWidget();
-  connect(this, &NodePanel::visibilityChanged, node_widget_->view(), &NodeView::CenterOnItemsBoundingRect);
+  node_widget_ = new NodeWidget(this);
+  connect(this, &NodePanel::shown, node_widget_->view(), &NodeView::CenterOnItemsBoundingRect);
 
   connect(node_widget_->view(), &NodeView::NodesSelected, this, &NodePanel::NodesSelected);
   connect(node_widget_->view(), &NodeView::NodesDeselected, this, &NodePanel::NodesDeselected);

app/panel/node/node.h

@@ -33,7 +33,7 @@ class NodePanel : public PanelWidget
 {
   Q_OBJECT
 public:
-  NodePanel(QWidget* parent);
+  NodePanel();
 
   NodeWidget *GetNodeWidget() const
   {

app/panel/panel.cpp

@@ -32,17 +32,16 @@
 
 namespace olive {
 
-#define super QDockWidget
+#define super KDDockWidgets::DockWidget
 
-PanelWidget::PanelWidget(const QString &object_name, QWidget *parent) :
-  super(parent),
+PanelWidget::PanelWidget(const QString &object_name) :
+  super(object_name),
   border_visible_(false),
   signal_instead_of_close_(false)
 {
-  setObjectName(object_name);
   setFocusPolicy(Qt::ClickFocus);
 
-  connect(this, &PanelWidget::visibilityChanged, this, &PanelWidget::PanelVisibilityChanged);
+  connect(this, &PanelWidget::shown, this, static_cast<void(PanelWidget::*)()>(&PanelWidget::setFocus));
 
   PanelManager::instance()->RegisterPanel(this);
 }
@@ -52,17 +51,6 @@ PanelWidget::~PanelWidget()
   PanelManager::instance()->UnregisterPanel(this);
 }
 
-void PanelWidget::SetMovementLocked(bool locked)
-{
-  if (locked) {
-    // Disable moving on QDockWidget
-    setFeatures(features() & ~QDockWidget::DockWidgetMovable);
-  } else {
-    // Re-enable moving on QDockWidget
-    setFeatures(features() | QDockWidget::DockWidgetMovable);
-  }
-}
-
 void PanelWidget::SetBorderVisible(bool enabled)
 {
   border_visible_ = enabled;
@@ -110,16 +98,9 @@ void PanelWidget::UpdateTitle()
   // If there's no subtitle, just use the title. Otherwise, we set a formatted combination of the two that can
   // differ based on translation
   if (subtitle_.isEmpty()) {
-    setWindowTitle(title_);
+    this->setTitle(title_);
   } else {
-    setWindowTitle(tr("%1: %2").arg(title_, subtitle_));
-  }
-}
-
-void PanelWidget::PanelVisibilityChanged(bool e)
-{
-  if (e) {
-    setFocus();
+    this->setTitle(tr("%1: %2").arg(title_, subtitle_));
   }
 }
 
@@ -134,7 +115,7 @@ void PanelWidget::closeEvent(QCloseEvent *event)
     event->ignore();
     emit CloseRequested();
   } else {
-    QDockWidget::closeEvent(event);
+    super::closeEvent(event);
   }
 }
 
@@ -143,7 +124,7 @@ void PanelWidget::changeEvent(QEvent *e)
   if (e->type() == QEvent::LanguageChange) {
     Retranslate();
   }
-  QDockWidget::changeEvent(e);
+  super::changeEvent(e);
 }
 
 void PanelWidget::Retranslate()

app/panel/panel.h

@@ -21,7 +21,7 @@
 #ifndef PANEL_WIDGET_H
 #define PANEL_WIDGET_H
 
-#include <QDockWidget>
+#include <kddockwidgets/DockWidget.h>
 #include <QEvent>
 
 #include "common/define.h"
@@ -31,7 +31,7 @@ namespace olive {
 /**
  * @brief A widget that is always dockable within the MainWindow.
  */
-class PanelWidget : public QDockWidget
+class PanelWidget : public KDDockWidgets::DockWidget
 {
   Q_OBJECT
 public:
@@ -43,15 +43,10 @@ public:
    * The PanelWidget's parent, enforced to help with memory handling. Most of the time this will be an instance of
    * MainWindow.
    */
-  PanelWidget(const QString& object_name, QWidget* parent);
+  PanelWidget(const QString& object_name);
 
   virtual ~PanelWidget() override;
 
-  /**
-   * @brief Set whether panel movement is locked or not
-   */
-  void SetMovementLocked(bool locked);
-
   /**
    * @brief Set visibility of panel's highlighted border, mostly used for showing panel focus
    *
@@ -246,9 +241,6 @@ private:
 
   bool signal_instead_of_close_;
 
-private slots:
-  void PanelVisibilityChanged(bool e);
-
 };
 
 }

app/panel/panelmanager.cpp

@@ -28,7 +28,6 @@ PanelManager* PanelManager::instance_ = nullptr;
 
 PanelManager::PanelManager(QObject *parent) :
   QObject(parent),
-  locked_(false),
   suppress_changed_signal_(false)
 {
 }
@@ -89,11 +88,6 @@ PanelWidget *PanelManager::GetPanelWithName(const QString &name) const
   return nullptr;
 }
 
-bool PanelManager::ArePanelsLocked()
-{
-  return locked_;
-}
-
 void PanelManager::CreateInstance()
 {
   instance_ = new PanelManager();
@@ -114,23 +108,10 @@ void PanelManager::RegisterPanel(PanelWidget *panel)
   // Add panel to the bottom of the focus history
   focus_history_.append(panel);
 
-  panel->SetMovementLocked(locked_);
-
-  // Get panel parent (it's assumed it has one)
-  QWidget *parent = panel->parentWidget();
-
-  // Sane default for panel size
-  panel->resize(parent->size() / 3);
-
   // We're about to center the panel relative to the parent (usually the main window), but for some
   // reason this requires the panel to be shown first.
   panel->show();
 
-  // Center the panel relative to the parent
-  QPoint parent_center = panel->mapFromGlobal(parent->mapToGlobal(parent->rect().center()));
-  QPoint panel_center = panel->rect().center();
-  panel->move(parent_center - panel_center);
-
   if (focus_history_.size() == 1) {
     // This is the first panel, focus it
     panel->SetBorderVisible(true);
@@ -151,54 +132,44 @@ void PanelManager::FocusChanged(QWidget *old, QWidget *now)
   PanelWidget* panel_cast_test;
 
   // Loop through widget's parent hierarchy
-  while (parent != nullptr) {
+  if (!focus_history_.empty()) {
+    while (parent != nullptr) {
 
-    // Use dynamic_cast to test if this object is a PanelWidget
-    panel_cast_test = dynamic_cast<PanelWidget*>(parent);
+      // Use dynamic_cast to test if this object is a PanelWidget
+      panel_cast_test = dynamic_cast<PanelWidget*>(parent);
 
-    if (panel_cast_test) {
+      if (panel_cast_test) {
 
-      if (focus_history_.first() != panel_cast_test) {
-        // If so, bump this to the top of the focus history
-        int panel_index = focus_history_.indexOf(panel_cast_test);
+        if (focus_history_.first() != panel_cast_test) {
+          // If so, bump this to the top of the focus history
+          int panel_index = focus_history_.indexOf(panel_cast_test);
 
-        // Disable highlight border on old panel
-        if (!focus_history_.isEmpty()) {
-          focus_history_.first()->SetBorderVisible(false);
+          // Disable highlight border on old panel
+          if (!focus_history_.isEmpty()) {
+            focus_history_.first()->SetBorderVisible(false);
+          }
+
+          // Enable new border's highlight
+          panel_cast_test->SetBorderVisible(true);
+
+          // If it's not in the focus history, prepend it, otherwise move it
+          if (panel_index == -1) {
+            focus_history_.prepend(panel_cast_test);
+          } else {
+            focus_history_.move(panel_index, 0);
+          }
+
+          if (!suppress_changed_signal_) {
+            emit FocusedPanelChanged(panel_cast_test);
+          }
         }
 
-        // Enable new border's highlight
-        panel_cast_test->SetBorderVisible(true);
-
-        // If it's not in the focus history, prepend it, otherwise move it
-        if (panel_index == -1) {
-          focus_history_.prepend(panel_cast_test);
-        } else {
-          focus_history_.move(panel_index, 0);
-        }
-
-        if (!suppress_changed_signal_) {
-          emit FocusedPanelChanged(panel_cast_test);
-        }
+        break;
       }
 
-      break;
-    }
-
-    parent = parent->parent();
-  }
-}
-
-void PanelManager::SetPanelsLocked(bool locked)
-{
-  foreach (PanelWidget* panel, focus_history_) {
-    // Only affect panels actually in our layout
-    if (!panel->isFloating()) {
-      panel->SetMovementLocked(locked);
+      parent = parent->parent();
     }
   }
-
-  locked_ = locked;
 }
 
 }

app/panel/panelmanager.h

@@ -86,11 +86,6 @@ public:
    */
   T* MostRecentlyFocused();
 
-  /**
-   * @brief Get whether panels are currently prevented from moving
-   */
-  bool ArePanelsLocked();
-
   /**
    * @brief Create PanelManager singleton instance
    */
@@ -137,11 +132,6 @@ public slots:
    */
   void FocusChanged(QWidget* old, QWidget* now);
 
-  /**
-   * @brief Sets whether panels should be prevented from moving
-   */
-  void SetPanelsLocked(bool locked);
-
 signals:
   /**
    * @brief Signal emitted when the currently focused panel changes
@@ -154,11 +144,6 @@ private:
    */
   QList<PanelWidget*> focus_history_;
 
-  /**
-   * @brief Internal panel movement is locked value
-   */
-  bool locked_;
-
   /**
    * @brief PanelManager singleton instance
    */

app/panel/param/param.cpp

@@ -24,14 +24,14 @@
 
 namespace olive {
 
-ParamPanel::ParamPanel(QWidget* parent) :
-  TimeBasedPanel(QStringLiteral("ParamPanel"), parent)
+ParamPanel::ParamPanel() :
+  TimeBasedPanel(QStringLiteral("ParamPanel"))
 {
-  NodeParamView* view = new NodeParamView();
+  NodeParamView* view = new NodeParamView(this);
   connect(view, &NodeParamView::FocusedNodeChanged, this, &ParamPanel::FocusedNodeChanged);
   connect(view, &NodeParamView::SelectedNodesChanged, this, &ParamPanel::SelectedNodesChanged);
   connect(view, &NodeParamView::RequestViewerToStartEditingText, this, &ParamPanel::RequestViewerToStartEditingText);
-  connect(this, &ParamPanel::visibilityChanged, view, &NodeParamView::UpdateElementY);
+  connect(this, &ParamPanel::shown, view, &NodeParamView::UpdateElementY);
   SetTimeBasedWidget(view);
 
   Retranslate();

app/panel/param/param.h

@@ -31,7 +31,7 @@ class ParamPanel : public TimeBasedPanel
 {
   Q_OBJECT
 public:
-  ParamPanel(QWidget* parent);
+  ParamPanel();
 
   NodeParamView *GetParamView() const
   {

app/panel/pixelsampler/pixelsamplerpanel.cpp

@@ -24,13 +24,14 @@
 
 namespace olive {
 
-PixelSamplerPanel::PixelSamplerPanel(QWidget *parent) :
-  PanelWidget(QStringLiteral("PixelSamplerPanel"), parent)
+PixelSamplerPanel::PixelSamplerPanel() :
+  PanelWidget(QStringLiteral("PixelSamplerPanel"))
 {
-  sampler_widget_ = new ManagedPixelSamplerWidget();
+  sampler_widget_ = new ManagedPixelSamplerWidget(this);
   SetWidgetWithPadding(sampler_widget_);
 
-  connect(this, &PixelSamplerPanel::visibilityChanged, Core::instance(), &Core::RequestPixelSamplingInViewers);
+  connect(this, &PixelSamplerPanel::shown, Core::instance(), []{Core::instance()->RequestPixelSamplingInViewers(true);});
+  connect(this, &PixelSamplerPanel::hidden, Core::instance(), []{Core::instance()->RequestPixelSamplingInViewers(false);});
   connect(Core::instance(), &Core::ColorPickerColorEmitted, this, &PixelSamplerPanel::SetValues);
 
   Retranslate();

app/panel/pixelsampler/pixelsamplerpanel.h

@@ -30,7 +30,7 @@ class PixelSamplerPanel : public PanelWidget
 {
   Q_OBJECT
 public:
-  PixelSamplerPanel(QWidget* parent = nullptr);
+  PixelSamplerPanel();
 
 public slots:
   void SetValues(const Color& reference, const Color& display);

app/panel/project/project.cpp

@@ -34,8 +34,8 @@
 
 namespace olive {
 
-ProjectPanel::ProjectPanel(QWidget *parent) :
-  PanelWidget(QStringLiteral("ProjectPanel"), parent)
+ProjectPanel::ProjectPanel(const QString &unique_name) :
+  PanelWidget(unique_name)
 {
   // Create main widget and its layout
   QWidget* central_widget = new QWidget(this);
@@ -83,7 +83,6 @@ void ProjectPanel::set_project(Project* p)
   if (project()) {
     disconnect(project(), &Project::NameChanged, this, &ProjectPanel::UpdateSubtitle);
     disconnect(project(), &Project::NameChanged, this, &ProjectPanel::ProjectNameChanged);
-    disconnect(project(), &Project::ModifiedChanged, this, &ProjectPanel::setWindowModified);
   }
 
   explorer_->set_project(p);
@@ -91,18 +90,11 @@ void ProjectPanel::set_project(Project* p)
   if (project()) {
     connect(project(), &Project::NameChanged, this, &ProjectPanel::UpdateSubtitle);
     connect(project(), &Project::NameChanged, this, &ProjectPanel::ProjectNameChanged);
-    connect(project(), &Project::ModifiedChanged, this, &ProjectPanel::setWindowModified);
   }
 
   UpdateSubtitle();
 
   emit ProjectNameChanged();
-
-  if (p) {
-    setWindowModified(p->is_modified());
-  } else {
-    setWindowModified(false);
-  }
 }
 
 Folder *ProjectPanel::get_root() const
@@ -197,7 +189,7 @@ void ProjectPanel::ShowNewMenu()
 void ProjectPanel::UpdateSubtitle()
 {
   if (project()) {
-    QString project_title = QStringLiteral("[*]%1").arg(project()->name());
+    QString project_title = QStringLiteral("%1").arg(project()->name());
 
     if (explorer_->get_root() != project()->root()) {
       QString folder_path;

app/panel/project/project.h

@@ -35,7 +35,7 @@ class ProjectPanel : public PanelWidget, public FootageManagementPanel
 {
   Q_OBJECT
 public:
-  ProjectPanel(QWidget* parent);
+  ProjectPanel(const QString &unique_name);
 
   Project* project() const;
   void set_project(Project* p);

app/panel/scope/scope.cpp

@@ -26,11 +26,11 @@
 
 namespace olive {
 
-ScopePanel::ScopePanel(QWidget* parent) :
-  PanelWidget(QStringLiteral("ScopePanel"), parent),
+ScopePanel::ScopePanel() :
+  PanelWidget(QStringLiteral("ScopePanel")),
   viewer_(nullptr)
 {
-  QWidget* central = new QWidget();
+  QWidget* central = new QWidget(this);
   setWidget(central);
 
   QVBoxLayout* layout = new QVBoxLayout(central);

app/panel/scope/scope.h

@@ -42,7 +42,7 @@ public:
     kTypeCount
   };
 
-  ScopePanel(QWidget* parent = nullptr);
+  ScopePanel();
 
   void SetType(Type t);
 

app/panel/sequenceviewer/sequenceviewer.cpp

@@ -23,8 +23,8 @@
 
 namespace olive {
 
-SequenceViewerPanel::SequenceViewerPanel(QWidget *parent) :
-  ViewerPanel(QStringLiteral("SequenceViewerPanel"), parent)
+SequenceViewerPanel::SequenceViewerPanel() :
+  ViewerPanel(QStringLiteral("SequenceViewerPanel"))
 {
   // Set strings
   Retranslate();

app/panel/sequenceviewer/sequenceviewer.h

@@ -29,7 +29,7 @@ class SequenceViewerPanel : public ViewerPanel
 {
   Q_OBJECT
 public:
-  SequenceViewerPanel(QWidget* parent);
+  SequenceViewerPanel();
 
 public slots:
   void StartCapture(const TimeRange &time, const Track::Reference &track);

app/panel/table/table.cpp

@@ -22,10 +22,10 @@
 
 namespace olive {
 
-NodeTablePanel::NodeTablePanel(QWidget* parent) :
-  TimeBasedPanel(QStringLiteral("NodeTablePanel"), parent)
+NodeTablePanel::NodeTablePanel() :
+  TimeBasedPanel(QStringLiteral("NodeTablePanel"))
 {
-  SetTimeBasedWidget(new NodeTableWidget());
+  SetTimeBasedWidget(new NodeTableWidget(this));
 
   Retranslate();
 }

app/panel/table/table.h

@@ -30,7 +30,7 @@ class NodeTablePanel : public TimeBasedPanel
 {
   Q_OBJECT
 public:
-  NodeTablePanel(QWidget* parent);
+  NodeTablePanel();
 
 public slots:
   void SelectNodes(const QVector<Node*>& nodes)

app/panel/taskmanager/taskmanager.cpp

@@ -24,8 +24,8 @@
 
 namespace olive {
 
-TaskManagerPanel::TaskManagerPanel(QWidget* parent) :
-  PanelWidget(QStringLiteral("TaskManagerPanel"), parent)
+TaskManagerPanel::TaskManagerPanel() :
+  PanelWidget(QStringLiteral("TaskManagerPanel"))
 {
   // Create task view
   view_ = new TaskView(this);

app/panel/taskmanager/taskmanager.h

@@ -33,7 +33,7 @@ class TaskManagerPanel : public PanelWidget
 {
   Q_OBJECT
 public:
-  TaskManagerPanel(QWidget* parent);
+  TaskManagerPanel();
 
 private:
   virtual void Retranslate() override;

app/panel/timebased/timebased.cpp

@@ -22,8 +22,8 @@
 
 namespace olive {
 
-TimeBasedPanel::TimeBasedPanel(const QString &object_name, QWidget *parent) :
-  PanelWidget(object_name, parent),
+TimeBasedPanel::TimeBasedPanel(const QString &object_name) :
+  PanelWidget(object_name),
   widget_(nullptr),
   show_and_raise_on_connect_(false)
 {

app/panel/timebased/timebased.h

@@ -30,7 +30,7 @@ class TimeBasedPanel : public PanelWidget
 {
   Q_OBJECT
 public:
-  TimeBasedPanel(const QString& object_name, QWidget *parent = nullptr);
+  TimeBasedPanel(const QString& object_name);
 
   virtual ~TimeBasedPanel() override;
 

app/panel/timeline/timeline.cpp

@@ -25,10 +25,10 @@
 
 namespace olive {
 
-TimelinePanel::TimelinePanel(QWidget *parent) :
-  TimeBasedPanel(QStringLiteral("TimelinePanel"), parent)
+TimelinePanel::TimelinePanel(const QString &name) :
+  TimeBasedPanel(name)
 {
-  TimelineWidget* tw = new TimelineWidget();
+  TimelineWidget* tw = new TimelineWidget(this);
   SetTimeBasedWidget(tw);
 
   Retranslate();

app/panel/timeline/timeline.h

@@ -33,7 +33,7 @@ class TimelinePanel : public TimeBasedPanel
 {
   Q_OBJECT
 public:
-  TimelinePanel(QWidget* parent);
+  TimelinePanel(const QString &name);
 
   inline TimelineWidget *timeline_widget() const
   {

app/panel/tool/tool.cpp

@@ -25,8 +25,8 @@
 
 namespace olive {
 
-ToolPanel::ToolPanel(QWidget *parent) :
-  PanelWidget(QStringLiteral("ToolPanel"), parent)
+ToolPanel::ToolPanel() :
+  PanelWidget(QStringLiteral("ToolPanel"))
 {
   Toolbar* t = new Toolbar(this);
 

app/panel/tool/tool.h

@@ -32,7 +32,7 @@ class ToolPanel : public PanelWidget
 {
   Q_OBJECT
 public:
-  ToolPanel(QWidget* parent);
+  ToolPanel();
 
 private:
   virtual void Retranslate() override;

app/panel/viewer/viewer.cpp

@@ -22,11 +22,11 @@
 
 namespace olive {
 
-ViewerPanel::ViewerPanel(const QString &object_name, QWidget *parent) :
-  ViewerPanelBase(object_name, parent)
+ViewerPanel::ViewerPanel(const QString &object_name) :
+  ViewerPanelBase(object_name)
 {
   // Set ViewerWidget as the central widget
-  ViewerWidget* vw = new ViewerWidget();
+  ViewerWidget* vw = new ViewerWidget(this);
   SetViewerWidget(vw);
 
   // Set strings

app/panel/viewer/viewer.h

@@ -33,11 +33,7 @@ namespace olive {
 class ViewerPanel : public ViewerPanelBase {
   Q_OBJECT
 public:
-  ViewerPanel(const QString& object_name, QWidget* parent);
-  ViewerPanel(QWidget *parent) :
-    ViewerPanel(QStringLiteral("ViewerPanel"), parent)
-  {
-  }
+  ViewerPanel(const QString& object_name);
 
 protected:
   virtual void Retranslate() override;

app/panel/viewer/viewerbase.cpp

@@ -26,8 +26,8 @@ namespace olive {
 
 #define super TimeBasedPanel
 
-ViewerPanelBase::ViewerPanelBase(const QString& object_name, QWidget *parent) :
-  super(object_name, parent)
+ViewerPanelBase::ViewerPanelBase(const QString& object_name) :
+  super(object_name)
 {
   connect(PanelManager::instance(), &PanelManager::FocusedPanelChanged, this, &ViewerPanelBase::FocusedPanelChanged);
 }

app/panel/viewer/viewerbase.h

@@ -31,7 +31,7 @@ class ViewerPanelBase : public TimeBasedPanel
 {
   Q_OBJECT
 public:
-  ViewerPanelBase(const QString& object_name, QWidget* parent = nullptr);
+  ViewerPanelBase(const QString& object_name);
 
   ViewerWidget *GetViewerWidget() const
   {

app/widget/audiomonitor/audiomonitor.cpp

@@ -36,7 +36,8 @@ const int kMaximumSmoothness = 8;
 
 QVector<AudioMonitor*> AudioMonitor::instances_;
 
-AudioMonitor::AudioMonitor() :
+AudioMonitor::AudioMonitor(QWidget *parent) :
+  QOpenGLWidget(parent),
   waveform_(nullptr),
   cached_channels_(0)
 {

app/widget/audiomonitor/audiomonitor.h

@@ -35,7 +35,7 @@ class AudioMonitor : public QOpenGLWidget
 {
   Q_OBJECT
 public:
-  AudioMonitor();
+  AudioMonitor(QWidget *parent = nullptr);
 
   virtual ~AudioMonitor() override;
 

app/widget/projectexplorer/projectexplorer.cpp

@@ -495,12 +495,12 @@ void ProjectExplorer::ReplaceSelectedFootage()
 
 void ProjectExplorer::OpenContextMenuItemInNewTab()
 {
-  Core::instance()->main_window()->OpenFolder(project(), static_cast<Folder*>(context_menu_items_.first()), false);
+  Core::instance()->main_window()->OpenFolder(static_cast<Folder*>(context_menu_items_.first()), false);
 }
 
 void ProjectExplorer::OpenContextMenuItemInNewWindow()
 {
-  Core::instance()->main_window()->OpenFolder(project(), static_cast<Folder*>(context_menu_items_.first()), true);
+  Core::instance()->main_window()->OpenFolder(static_cast<Folder*>(context_menu_items_.first()), true);
 }
 
 void ProjectExplorer::ContextMenuStartProxy(QAction *a)

app/window/mainwindow/mainmenu.cpp

@@ -188,8 +188,6 @@ MainMenu::MainMenu(MainWindow *parent) :
   window_menu_ = new Menu(this, this, &MainMenu::WindowMenuAboutToShow);
   window_menu_separator_ = window_menu_->addSeparator();
   window_maximize_panel_item_ = window_menu_->AddItem("maximizepanel", parent, &MainWindow::ToggleMaximizedPanel, tr("`"));
-  window_lock_layout_item_ = window_menu_->AddItem("lockpanels", PanelManager::instance(), &PanelManager::SetPanelsLocked);
-  window_lock_layout_item_->setCheckable(true);
   window_menu_->addSeparator();
   window_reset_layout_item_ = window_menu_->AddItem("resetdefaultlayout", parent, &MainWindow::SetDefaultLayout);
 
@@ -403,7 +401,7 @@ void MainMenu::WindowMenuAboutToShow()
   // Alphabetize actions - keeps actions in a consistent order since PanelManager::panels() is
   // ordered from most recently focused to least, which may be confusing user experience.
   foreach (PanelWidget* panel, PanelManager::instance()->panels()) {
-    QAction* panel_action = panel->toggleViewAction();
+    QAction* panel_action = panel->toggleAction();
 
     bool inserted = false;
 
@@ -422,8 +420,6 @@ void MainMenu::WindowMenuAboutToShow()
 
   // Add new items
   window_menu_->insertActions(window_menu_separator_, panel_actions);
-
-  window_lock_layout_item_->setChecked(PanelManager::instance()->ArePanelsLocked());
 }
 
 void MainMenu::PopulateOpenRecent()
@@ -757,7 +753,6 @@ void MainMenu::Retranslate()
   // Window menu
   window_menu_->setTitle(tr("&Window"));
   window_maximize_panel_item_->setText(tr("Maximize Panel"));
-  window_lock_layout_item_->setText(tr("Lock Panels"));
   window_reset_layout_item_->setText(tr("Reset to Default Layout"));
 
   // Tools menu

app/window/mainwindow/mainmenu.h

@@ -262,7 +262,6 @@ private:
   Menu* window_menu_;
   QAction* window_menu_separator_;
   QAction* window_maximize_panel_item_;
-  QAction* window_lock_layout_item_;
   QAction* window_reset_layout_item_;
 
   Menu* tools_menu_;

app/window/mainwindow/mainwindow.cpp

@@ -36,8 +36,10 @@
 
 namespace olive {
 
+#define super KDDockWidgets::MainWindow
+
 MainWindow::MainWindow(QWidget *parent) :
-  QMainWindow(parent),
+  super(QStringLiteral("OliveMain"), KDDockWidgets::MainWindowOption_None, parent),
   project_(nullptr)
 {
   // Resizes main window to desktop geometry on startup. Fixes the following issues:
@@ -57,18 +59,6 @@ MainWindow::MainWindow(QWidget *parent) :
 
   first_show_ = true;
 
-  // Create empty central widget - we don't actually want a central widget (so we set its maximum
-  // size to 0,0) but some of Qt's docking/undocking fails without it
-  QWidget* centralWidget = new QWidget(this);
-  centralWidget->setMaximumSize(QSize(0, 0));
-  setCentralWidget(centralWidget);
-
-  // Set tabs to be on top of panels (default behavior is bottom)
-  setTabPosition(Qt::AllDockWidgetAreas, QTabWidget::North);
-
-  // Allow panels to be tabbed within each other
-  setDockNestingEnabled(true);
-
   // Create and set main menu
   MainMenu* main_menu = new MainMenu(this);
   setMenuBar(main_menu);
@@ -82,19 +72,19 @@ MainWindow::MainWindow(QWidget *parent) :
   setStatusBar(status_bar);
 
   // Create standard panels
-  node_panel_ = new NodePanel(this);
-  footage_viewer_panel_ = new FootageViewerPanel(this);
-  param_panel_ = new ParamPanel(this);
-  curve_panel_ = new CurvePanel(this);
-  sequence_viewer_panel_ = new SequenceViewerPanel(this);
-  multicam_panel_ = new MulticamPanel(this);
-  pixel_sampler_panel_ = new PixelSamplerPanel(this);
-  project_panel_ = new ProjectPanel(this);
-  tool_panel_ = new ToolPanel(this);
-  task_man_panel_ = new TaskManagerPanel(this);
+  node_panel_ = new NodePanel();
+  footage_viewer_panel_ = new FootageViewerPanel();
+  param_panel_ = new ParamPanel();
+  curve_panel_ = new CurvePanel();
+  sequence_viewer_panel_ = new SequenceViewerPanel();
+  multicam_panel_ = new MulticamPanel();
+  pixel_sampler_panel_ = new PixelSamplerPanel();
+  project_panel_ = new ProjectPanel(QStringLiteral("ProjectPanel"));
+  tool_panel_ = new ToolPanel();
+  task_man_panel_ = new TaskManagerPanel();
   AppendTimelinePanel();
-  audio_monitor_panel_ = new AudioMonitorPanel(this);
-  scope_panel_ = new ScopePanel(this);
+  audio_monitor_panel_ = new AudioMonitorPanel();
+  scope_panel_ = new ScopePanel();
 
   // Make node-related connections
   connect(node_panel_, &NodePanel::NodeSelectionChangedWithContexts, param_panel_, &ParamPanel::SetSelectedNodes);
@@ -137,7 +127,7 @@ MainWindow::~MainWindow()
 void MainWindow::LoadLayout(const MainWindowLayoutInfo &info)
 {
   foreach (Folder* folder, info.open_folders()) {
-    OpenFolder(folder->project(), folder, true);
+    OpenFolder(folder, true);
   }
 
   foreach (Sequence *sequence, info.open_sequences()) {
@@ -155,34 +145,52 @@ void MainWindow::LoadLayout(const MainWindowLayoutInfo &info)
     }
   }
 
-  restoreState(info.state());
+  KDDockWidgets::LayoutSaver().restoreLayout(qUncompress(info.state()));
+}
+
+QString TransformNameForSerialization(const QString &unique, int i)
+{
+  return QStringLiteral("%1:%2").arg(unique.split(':').at(0), QString::number(i));
+}
+
+void CorrectPanelDataIfNecessary(const QString &unique_name, int index, MainWindowLayoutInfo &info, QByteArray &layout)
+{
+  QString corrected = TransformNameForSerialization(unique_name, index);
+  if (corrected != unique_name) {
+    info.move_panel_data(unique_name, corrected);
+    layout.replace(unique_name.toUtf8(), corrected.toUtf8());
+  }
 }
 
 MainWindowLayoutInfo MainWindow::SaveLayout() const
 {
   MainWindowLayoutInfo info;
 
-  foreach (ProjectPanel* panel, folder_panels_) {
-    if (panel->project()) {
-      info.add_folder(panel->get_root());
-    }
-  }
-
-  foreach (TimelinePanel* panel, timeline_panels_) {
-    if (panel->GetConnectedViewer()) {
-      info.add_sequence(panel->GetSequence());
-    }
-  }
-
-  for (auto it=viewer_panels_.cbegin(); it!=viewer_panels_.cend(); it++) {
-    info.add_viewer((*it)->GetConnectedViewer());
-  }
+  QByteArray layout = premaximized_state_.isEmpty() ? KDDockWidgets::LayoutSaver().serializeLayout() : premaximized_state_;
 
   foreach (PanelWidget *panel, PanelManager::instance()->panels()) {
-    info.set_panel_data(panel->objectName(), panel->SaveData());
+    info.set_panel_data(panel->uniqueName(), panel->SaveData());
   }
 
-  info.set_state(premaximized_state_.isEmpty() ? this->saveState() : premaximized_state_);
+  for (int i = 0; i < folder_panels_.size(); i++) {
+    auto panel = folder_panels_.at(i);
+    info.add_folder(panel->get_root());
+    CorrectPanelDataIfNecessary(panel->uniqueName(), i, info, layout);
+  }
+
+  for (int i = 0; i < timeline_panels_.size(); i++) {
+    auto panel = timeline_panels_.at(i);
+    info.add_sequence(panel->GetSequence());
+    CorrectPanelDataIfNecessary(panel->uniqueName(), i, info, layout);
+  }
+
+  for (int i = 0; i < viewer_panels_.size(); i++) {
+    auto panel = viewer_panels_.at(i);
+    info.add_viewer(panel->GetConnectedViewer());
+    CorrectPanelDataIfNecessary(panel->uniqueName(), i, info, layout);
+  }
+
+  info.set_state(qCompress(layout));
 
   return info;
 }
@@ -241,17 +249,17 @@ bool MainWindow::IsSequenceOpen(Sequence *sequence) const
   return false;
 }
 
-void MainWindow::OpenFolder(Project* p, Folder *i, bool floating)
+void MainWindow::OpenFolder(Folder *i, bool floating)
 {
-  ProjectPanel* panel = AppendPanelInternal(folder_panels_);
+  ProjectPanel* panel = AppendPanelInternal(QStringLiteral("FolderPanel"), folder_panels_);
 
-  panel->set_project(p);
+  panel->set_project(i->project());
   panel->set_root(i);
 
   if (floating) {
     panel->setFloating(floating);
   } else {
-    tabifyDockWidget(project_panel_, panel);
+    project_panel_->addDockWidgetAsTab(panel);
   }
 
   // If the panel is closed, just destroy it
@@ -275,17 +283,12 @@ void MainWindow::OpenNodeInViewer(ViewerOutput *node)
     existing->raise();
   } else {
     // Create a viewer for this node
-    ViewerPanel* viewer = new ViewerPanel(this);
+    ViewerPanel* viewer = AppendPanelInternal(QStringLiteral("ViewerPanel"), viewer_panels_);
 
-    viewer->SetSignalInsteadOfClose(true);
-    viewer->setFloating(true);
-    viewer->setVisible(true);
     viewer->ConnectViewerNode(node);
 
     connect(viewer, &ViewerPanel::CloseRequested, this, &MainWindow::ViewerCloseRequested);
     connect(node, &ViewerOutput::RemovedFromGraph, this, &MainWindow::ViewerWithPanelRemovedFromGraph);
-
-    viewer_panels_.append(viewer);
   }
 }
 
@@ -300,6 +303,8 @@ void MainWindow::SetFullscreen(bool fullscreen)
 
 void MainWindow::ToggleMaximizedPanel()
 {
+  KDDockWidgets::LayoutSaver saver;
+
   if (premaximized_state_.isEmpty()) {
     // Assume nothing is maximized at the moment
 
@@ -322,12 +327,12 @@ void MainWindow::ToggleMaximizedPanel()
     }
 
     // Save the current state so it can be restored later
-    premaximized_state_ = saveState();
+    premaximized_state_ = saver.serializeLayout();
 
     // For every other panel that is on the main window, hide it
     foreach (PanelWidget* panel, PanelManager::instance()->panels()) {
       if (!panel->isFloating() && panel != currently_hovered) {
-        panel->setVisible(false);
+        panel->close();
       }
     }
   } else {
@@ -336,7 +341,7 @@ void MainWindow::ToggleMaximizedPanel()
 
     // Assume we are currently maximized, restore the state
     PanelManager::instance()->SetSuppressChangedSignal(true);
-    restoreState(premaximized_state_);
+    saver.restoreLayout(premaximized_state_);
     premaximized_state_.clear();
 
     currently_focused_panel->raise();
@@ -593,16 +598,17 @@ void MainWindow::FolderPanelCloseRequested()
 {
   ProjectPanel* panel = static_cast<ProjectPanel*>(sender());
   RemovePanelInternal(folder_panels_, panel);
-  removeDockWidget(panel);
   panel->deleteLater();
 }
 
 TimelinePanel* MainWindow::AppendTimelinePanel()
 {
-  TimelinePanel* panel = AppendPanelInternal(timeline_panels_);
+  TimelinePanel* panel = AppendPanelInternal(QStringLiteral("TimelinePanel"), timeline_panels_);
 
-  if (!timeline_panels_.isEmpty()) {
-    tabifyDockWidget(timeline_panels_.last(), panel);
+  if (timeline_panels_.size() > 1) {
+    timeline_panels_.last()->addDockWidgetAsTab(panel);
+  } else {
+    panel->SetSignalInsteadOfClose(false);
   }
 
   connect(panel, &PanelWidget::CloseRequested, this, &MainWindow::TimelineCloseRequested);
@@ -734,7 +740,6 @@ void MainWindow::SaveCustomShortcuts()
   } else {
     qCritical() << "Failed to save custom keyboard shortcuts";
   }
-
 }
 
 void MainWindow::UpdateAudioMonitorParams(ViewerOutput *viewer)
@@ -804,62 +809,52 @@ void MainWindow::FocusedPanelChanged(PanelWidget *panel)
 
 void MainWindow::SetDefaultLayout()
 {
-  footage_viewer_panel_->show();
-  addDockWidget(Qt::TopDockWidgetArea, footage_viewer_panel_);
+  KDDockWidgets::InitialOption o;
+  o.preferredSize = QSize(0, centralAreaGeometry().height());
 
-  param_panel_->show();
-  tabifyDockWidget(footage_viewer_panel_, param_panel_);
-
-  node_panel_->show();
-  tabifyDockWidget(param_panel_, node_panel_);
+  // Top left - Tabify footage viewer, param panel, and node panel
+  addDockWidget(footage_viewer_panel_, KDDockWidgets::Location_OnTop, nullptr, o);
+  footage_viewer_panel_->addDockWidgetAsTab(param_panel_);
+  footage_viewer_panel_->addDockWidgetAsTab(node_panel_);
   param_panel_->raise();
 
-  curve_panel_->hide();
-  curve_panel_->setFloating(true);
-  addDockWidget(Qt::TopDockWidgetArea, curve_panel_);
+  // Top right - sequence viewer
+  addDockWidget(sequence_viewer_panel_, KDDockWidgets::Location_OnRight, footage_viewer_panel_, o);
 
-  scope_panel_->hide();
-  scope_panel_->setFloating(true);
-  addDockWidget(Qt::TopDockWidgetArea, scope_panel_);
+  // Bottom center - timelines
+  addDockWidget(timeline_panels_.first(), KDDockWidgets::Location_OnBottom);
 
-  multicam_panel_->hide();
-  multicam_panel_->setFloating(true);
-  addDockWidget(Qt::TopDockWidgetArea, multicam_panel_);
+  // Left of timeline - tool panel
+  o.preferredSize = QSize(1, 0);
+  addDockWidget(tool_panel_, KDDockWidgets::Location_OnLeft, timeline_panels_.first(), o);
 
-  sequence_viewer_panel_->show();
-  addDockWidget(Qt::TopDockWidgetArea, sequence_viewer_panel_);
+  // Right of timeline - audio monitor
+  addDockWidget(audio_monitor_panel_, KDDockWidgets::Location_OnRight, timeline_panels_.first(), o);
 
-  pixel_sampler_panel_->hide();
-  pixel_sampler_panel_->setFloating(true);
-  addDockWidget(Qt::TopDockWidgetArea, pixel_sampler_panel_);
+  // Bottom left - project panel
+  addDockWidget(project_panel_, KDDockWidgets::Location_OnLeft, tool_panel_);
 
-  project_panel_->show();
-  addDockWidget(Qt::BottomDockWidgetArea, project_panel_);
+  // Hidden panels
+  pixel_sampler_panel_->close();
+  task_man_panel_->close();
+  curve_panel_->close();
+  scope_panel_->close();
+  multicam_panel_->close();
+  for (auto it = folder_panels_.cbegin(); it != folder_panels_.cend(); it++) {
+    (*it)->close();
+  }
+  for (auto it = viewer_panels_.cbegin(); it != viewer_panels_.cend(); it++) {
+    (*it)->close();
+  }
+  for (auto it = timeline_panels_.cbegin(); it != timeline_panels_.cend(); it++) {
+    auto p = *it;
+    if (p != timeline_panels_.first()) {
+      p->addDockWidgetAsTab(p);
+    }
+  }
 
-  tool_panel_->show();
-  addDockWidget(Qt::BottomDockWidgetArea, tool_panel_);
-
-  timeline_panels_.first()->show();
-  addDockWidget(Qt::BottomDockWidgetArea, timeline_panels_.first());
-
-  task_man_panel_->hide();
-  task_man_panel_->setFloating(true);
-  addDockWidget(Qt::BottomDockWidgetArea, task_man_panel_);
-
-  audio_monitor_panel_->show();
-  addDockWidget(Qt::BottomDockWidgetArea, audio_monitor_panel_);
-
-  resizeDocks({param_panel_, sequence_viewer_panel_},
-  {width()/2, width()/2},
-              Qt::Horizontal);
-
-  resizeDocks({project_panel_, tool_panel_, timeline_panels_.first(), audio_monitor_panel_},
-  {width()/4, 1, width(), 1},
-              Qt::Horizontal);
-
-  resizeDocks({node_panel_, project_panel_},
-  {height()/2, height()/2},
-              Qt::Vertical);
+  // Set to unmaximized panels
+  premaximized_state_.clear();
 }
 
 void MainWindow::showEvent(QShowEvent *e)
@@ -889,24 +884,15 @@ void MainWindow::showEvent(QShowEvent *e)
   }
 }
 
-void UpdatePanelName(PanelWidget *panel, int index)
-{
-  QString old_name = panel->objectName();
-  QString new_name = QStringLiteral("%1:%2").arg(old_name.split(':').at(0), QString::number(index));
-  qDebug() << "renaming" << old_name << "to" << new_name;
-  panel->setObjectName(new_name);
-}
-
 template<typename T>
-T *MainWindow::AppendPanelInternal(QList<T*>& list)
+T *MainWindow::AppendPanelInternal(const QString &panel_name, QList<T*>& list)
 {
-  T* panel = new T(this);
+  T* panel = new T(TransformNameForSerialization(panel_name, list.size()));
 
   // For some reason raise() on its own doesn't do anything, we need both
   panel->show();
   panel->raise();
 
-  UpdatePanelName(panel, list.size());
   list.append(panel);
 
   // Let us handle the panel closing rather than the panel itself
@@ -918,14 +904,7 @@ T *MainWindow::AppendPanelInternal(QList<T*>& list)
 template<typename T>
 void MainWindow::RemovePanelInternal(QList<T *> &list, T *panel)
 {
-  int index = list.indexOf(panel);
-
-  if (index != -1) {
-    list.removeAt(index);
-    for (int i = index; i < list.size(); i++) {
-      UpdatePanelName(list.at(i), i);
-    }
-  }
+  list.removeOne(panel);
 }
 
 }

app/window/mainwindow/mainwindow.h

@@ -21,7 +21,8 @@
 #ifndef MAINWINDOW_H
 #define MAINWINDOW_H
 
-#include <QMainWindow>
+#include <kddockwidgets/Config.h>
+#include <kddockwidgets/MainWindow.h>
 
 #include "mainwindowlayoutinfo.h"
 #include "node/project/project.h"
@@ -50,7 +51,7 @@ namespace olive {
 /**
  * @brief Olive's main window responsible for docking widgets and the main menu bar.
  */
-class MainWindow : public QMainWindow
+class MainWindow : public KDDockWidgets::MainWindow
 {
   Q_OBJECT
 public:
@@ -68,7 +69,7 @@ public:
 
   bool IsSequenceOpen(Sequence* sequence) const;
 
-  void OpenFolder(Project* p, Folder *i, bool floating);
+  void OpenFolder(Folder *i, bool floating);
 
   void OpenNodeInViewer(ViewerOutput* node);
 
@@ -117,7 +118,7 @@ private:
   TimelinePanel* AppendTimelinePanel();
 
   template <typename T>
-  T* AppendPanelInternal(QList<T*>& list);
+  T* AppendPanelInternal(const QString &panel_name, QList<T*>& list);
 
   template <typename T>
   void RemovePanelInternal(QList<T*>& list, T *panel);

app/window/mainwindow/mainwindowlayoutinfo.cpp

@@ -176,6 +176,13 @@ void MainWindowLayoutInfo::set_panel_data(const QString &id, const PanelWidget::
   panel_data_[id] = data;
 }
 
+void MainWindowLayoutInfo::move_panel_data(const QString &old, const QString &now)
+{
+  PanelWidget::Info tmp = panel_data_.at(old);
+  panel_data_.erase(old);
+  panel_data_[now] = tmp;
+}
+
 void MainWindowLayoutInfo::set_state(const QByteArray &layout)
 {
   state_ = layout;

app/window/mainwindow/mainwindowlayoutinfo.h

@@ -24,6 +24,8 @@ public:
 
   void set_panel_data(const QString &id, const PanelWidget::Info &data);
 
+  void move_panel_data(const QString &old, const QString &now);
+
   void set_state(const QByteArray& layout);
 
   const std::vector<Folder*>& open_folders() const