Add initial functionality for Auto hide

- Add left and right side tab widgets
- Add overlay dock and overlay dock widget behavior

src/CMakeLists.txt

@@ -27,6 +27,9 @@ set(ads_SRCS
     FloatingDragPreview.cpp
     IconProvider.cpp
     DockComponentsFactory.cpp
+    SideTabBar.cpp
+    DockWidgetSideTab.cpp
+    OverlayDockContainer.cpp
     ads.qrc
 )
 set(ads_HEADERS
@@ -48,6 +51,9 @@ set(ads_HEADERS
     FloatingDragPreview.h
     IconProvider.h
     DockComponentsFactory.h
+    SideTabBar.h
+    DockWidgetSideTab.h
+    OverlayDockContainer.h
 )
 add_compile_options("$<$<CXX_COMPILER_ID:MSVC>:/utf-8>")
 if (UNIX AND NOT APPLE)

src/DockAreaTitleBar.cpp

@@ -52,6 +52,7 @@
 #include "IconProvider.h"
 #include "DockComponentsFactory.h"
 #include "DockFocusController.h"
+#include "OverlayDockContainer.h"
 
 #include <iostream>
 
@@ -65,6 +66,7 @@ struct DockAreaTitleBarPrivate
 {
 	CDockAreaTitleBar* _this;
 	QPointer<tTitleBarButton> TabsMenuButton;
+	QPointer<tTitleBarButton> AutoHideButton;
 	QPointer<tTitleBarButton> UndockButton;
 	QPointer<tTitleBarButton> CloseButton;
 	QBoxLayout* Layout;
@@ -162,6 +164,19 @@ void DockAreaTitleBarPrivate::createButtons()
 	_this->connect(TabsMenuButton->menu(), SIGNAL(triggered(QAction*)),
 		SLOT(onTabsMenuActionTriggered(QAction*)));
 
+	// AutoHide Button
+	const auto autoHideEnabled = testConfigFlag(CDockManager::DockContainerHasRightSideBar) || testConfigFlag(CDockManager::DockContainerHasLeftSideBar);
+	AutoHideButton = new CTitleBarButton(testConfigFlag(CDockManager::DockAreaHasAutoHideButton) && autoHideEnabled);
+	AutoHideButton->setObjectName("autoHideButton");
+	AutoHideButton->setAutoRaise(true);
+	AutoHideButton->setCheckable(true);
+	AutoHideButton->setChecked(false);
+	internal::setToolTip(AutoHideButton, QObject::tr("Toggle Auto Hide Group"));
+	internal::setButtonIcon(AutoHideButton, QStyle::SP_DialogOkButton, ads::DockAreaUndockIcon);
+	AutoHideButton->setSizePolicy(ButtonSizePolicy);
+	Layout->addWidget(AutoHideButton, 0);
+	_this->connect(AutoHideButton, SIGNAL(toggled(bool)),  SLOT(onAutoHideButtonClicked(bool)));
+
 	// Undock button
 	UndockButton = new CTitleBarButton(testConfigFlag(CDockManager::DockAreaHasUndockButton));
 	UndockButton->setObjectName("detachGroupButton");
@@ -249,6 +264,10 @@ IFloatingWidget* DockAreaTitleBarPrivate::makeAreaFloating(const QPoint& Offset,
 //============================================================================
 void DockAreaTitleBarPrivate::startFloating(const QPoint& Offset)
 {
+	if (DockArea->overlayDockContainer() != nullptr)
+	{
+		DockArea->overlayDockContainer()->hide();
+	}
 	FloatingWidget = makeAreaFloating(Offset, DraggingFloatingWidget);
 }
 
@@ -438,6 +457,14 @@ void CDockAreaTitleBar::onCurrentTabChanged(int Index)
 	updateDockWidgetActionsButtons();
 }
 
+void CDockAreaTitleBar::onAutoHideButtonClicked(bool Checked)
+{
+	if (Checked != d->DockArea->isOverlayed())
+	{
+        d->DockArea->toggleAutoHideArea();
+	}
+}
+
 
 //============================================================================
 QAbstractButton* CDockAreaTitleBar::button(TitleBarButton which) const
@@ -447,6 +474,7 @@ QAbstractButton* CDockAreaTitleBar::button(TitleBarButton which) const
 	case TitleBarButtonTabsMenu: return d->TabsMenuButton;
 	case TitleBarButtonUndock: return d->UndockButton;
 	case TitleBarButtonClose: return d->CloseButton;
+	case TitleBarButtonAutoHide: return d->AutoHideButton;
 	default:
 		return nullptr;
 	}
@@ -523,7 +551,8 @@ void CDockAreaTitleBar::mouseMoveEvent(QMouseEvent* ev)
 	// sense to move it to a new floating widget and leave this one
 	// empty
 	if (d->DockArea->dockContainer()->isFloating()
-	 && d->DockArea->dockContainer()->visibleDockAreaCount() == 1)
+	 && d->DockArea->dockContainer()->visibleDockAreaCount() == 1 
+     && !d->DockArea->isOverlayed())
 	{
 		return;
 	}

src/DockAreaTitleBar.h

@@ -60,9 +60,10 @@ private Q_SLOTS:
 	void onUndockButtonClicked();
 	void onTabsMenuActionTriggered(QAction* Action);
 	void onCurrentTabChanged(int Index);
+	void onAutoHideButtonClicked(bool Checked);
 
 protected:
-		/**
+    /**
 	 * Stores mouse position to detect dragging
 	 */
 	virtual void mousePressEvent(QMouseEvent* ev) override;

src/DockAreaWidget.cpp

@@ -54,6 +54,9 @@
 #include "DockAreaTitleBar.h"
 #include "DockComponentsFactory.h"
 #include "DockWidgetTab.h"
+#include "SideTabBar.h"
+#include "DockWidgetSideTab.h"
+#include "OverlayDockContainer.h"
 
 
 namespace ads
@@ -249,6 +252,7 @@ struct DockAreaWidgetPrivate
 	DockAreaLayout*		ContentsLayout	= nullptr;
 	CDockAreaTitleBar*	TitleBar		= nullptr;
 	CDockManager*		DockManager		= nullptr;
+	COverlayDockContainer* OverlayDockContainer = nullptr;
 	bool UpdateTitleBarButtons = false;
 	DockWidgetAreas		AllowedAreas	= DefaultAllowedAreas;
 	QSize MinSizeHint;
@@ -358,6 +362,7 @@ void DockAreaWidgetPrivate::updateTitleBarButtonStates()
 		_this->features().testFlag(CDockWidget::DockWidgetClosable));
 	TitleBar->button(TitleBarButtonUndock)->setEnabled(
 		_this->features().testFlag(CDockWidget::DockWidgetFloatable));
+	TitleBar->button(TitleBarButtonUndock)->setVisible(!_this->isOverlayed());
 	TitleBar->updateDockWidgetActionsButtons();
 	UpdateTitleBarButtons = false;
 }
@@ -404,6 +409,24 @@ CDockContainerWidget* CDockAreaWidget::dockContainer() const
 	return internal::findParent<CDockContainerWidget*>(this);
 }
 
+//============================================================================
+COverlayDockContainer* CDockAreaWidget::overlayDockContainer() const
+{
+	return d->OverlayDockContainer;
+}
+
+//============================================================================
+bool CDockAreaWidget::isOverlayed() const
+{
+	return d->OverlayDockContainer != nullptr;
+}
+
+//============================================================================
+void CDockAreaWidget::setOverlayDockContainer(COverlayDockContainer* OverlayDockContainer)
+{
+	d->OverlayDockContainer = OverlayDockContainer;
+}
+
 
 //============================================================================
 void CDockAreaWidget::addDockWidget(CDockWidget* DockWidget)
@@ -530,6 +553,10 @@ void CDockAreaWidget::hideAreaWithNoVisibleContent()
 	{
 		FloatingWidget->hide();
 	}
+	if (isOverlayed())
+	{
+		overlayDockContainer()->hide();
+	}
 }
 
 
@@ -757,7 +784,8 @@ void CDockAreaWidget::updateTitleBarVisibility()
 		bool Hidden = Container->hasTopLevelDockWidget() && (Container->isFloating()
 			|| CDockManager::testConfigFlag(CDockManager::HideSingleCentralWidgetTitleBar));
 		Hidden |= (d->Flags.testFlag(HideSingleWidgetTitleBar) && openDockWidgetsCount() == 1);
-		d->TitleBar->setVisible(!Hidden);
+		d->TitleBar->setVisible(isOverlayed() ? true : !Hidden); // Titlebar must always be visible when overlayed so it can be dragged
+        d->TitleBar->tabBar()->setVisible(isOverlayed() ? false : !Hidden);  // Never show tab bar when overlayed
 	}
 }
 
@@ -783,6 +811,11 @@ void CDockAreaWidget::saveState(QXmlStreamWriter& s) const
 	s.writeAttribute("Current", Name);
 	// To keep the saved XML data small, we only save the allowed areas and the
 	// dock area flags if the values are different from the default values
+	if (isOverlayed())
+	{
+		overlayDockContainer()->saveState(s);
+	}
+
 	if (d->AllowedAreas != DefaultAllowedAreas)
 	{
 		s.writeAttribute("AllowedAreas", QString::number(d->AllowedAreas, 16));
@@ -957,8 +990,9 @@ void CDockAreaWidget::closeArea()
 {
 	// If there is only one single dock widget and this widget has the
 	// DeleteOnClose feature, then we delete the dock widget now
+	// Note: Auto hide and overlays do not support dock widget delete on close
 	auto OpenDockWidgets = openedDockWidgets();
-    if (OpenDockWidgets.count() == 1 && OpenDockWidgets[0]->features().testFlag(CDockWidget::DockWidgetDeleteOnClose))
+    if (OpenDockWidgets.count() == 1 && OpenDockWidgets[0]->features().testFlag(CDockWidget::DockWidgetDeleteOnClose) && !isOverlayed())
 	{
 		OpenDockWidgets[0]->closeDockWidgetInternal();
 	}
@@ -966,7 +1000,7 @@ void CDockAreaWidget::closeArea()
 	{
         for (auto DockWidget : openedDockWidgets())
         {
-            if (DockWidget->features().testFlag(CDockWidget::DockWidgetDeleteOnClose) && DockWidget->features().testFlag(CDockWidget::DockWidgetForceCloseWithArea))
+            if (DockWidget->features().testFlag(CDockWidget::DockWidgetDeleteOnClose) && DockWidget->features().testFlag(CDockWidget::DockWidgetForceCloseWithArea) && !isOverlayed())
                 DockWidget->closeDockWidgetInternal();
             else
                 DockWidget->toggleView(false);
@@ -974,6 +1008,31 @@ void CDockAreaWidget::closeArea()
     }
 }
 
+//============================================================================
+void CDockAreaWidget::toggleAutoHideArea()
+{
+	const auto area = dockContainer()->getDockAreaPosition(this);
+	for (const auto DockWidget : openedDockWidgets())
+	{
+		onAutoHideToggleRequested(DockWidget, !isOverlayed(), area);
+	}
+}
+
+//============================================================================
+void CDockAreaWidget::onAutoHideToggleRequested(CDockWidget* DockWidget, bool Enable, SideTabBarArea area) 
+{
+    if (Enable)
+    {
+        dockContainer()->sideTabBar(area)->insertSideTab(0, DockWidget->sideTabWidget());
+        DockWidget->sideTabWidget()->show();
+        dockContainer()->createDockWidgetOverlayContainer(area, DockWidget);
+        toggleView(false);
+    }
+    else
+	{
+        overlayDockContainer()->moveContentsToParent();
+	}
+}
 
 //============================================================================
 void CDockAreaWidget::closeOtherAreas()

src/DockAreaWidget.h

@@ -65,6 +65,7 @@ private:
 	friend class CDockWidget;
 	friend struct DockManagerPrivate;
 	friend class CDockManager;
+	friend class COverlayDockContainer;
 	void onDockWidgetFeaturesChanged();
 
 private Q_SLOTS:
@@ -186,6 +187,23 @@ public:
 	 */
 	CDockContainerWidget* dockContainer() const;
 
+	/**
+	 * Returns the overlay dock container widget this dock area widget belongs to or 0
+	 * if there is no
+	 */
+	COverlayDockContainer* overlayDockContainer() const; 
+
+	/**
+	 * Returns true if the dock area exists in an overlay dock container
+	 */
+	bool isOverlayed() const;
+
+
+	/**
+	 * Sets the current overlay dock container
+	 */
+	void setOverlayDockContainer(COverlayDockContainer* OverlayDockContainer);
+
     /**
      * Returns the largest minimumSizeHint() of the dock widgets in this
      * area.
@@ -337,6 +355,16 @@ public Q_SLOTS:
 	void closeArea();
 
 	/**
+	 * Toggles the Auto hides behaviour of the dock area and all dock widgets in this area
+	 */
+	void toggleAutoHideArea();
+
+	/**
+	 * Auto hides the dock area and all dock widgets in this area
+	 */
+    void onAutoHideToggleRequested(CDockWidget* DockWidget, bool Enable, SideTabBarArea area);
+
+    /**
 	 * This function closes all other areas except of this area
 	 */
 	void closeOtherAreas();

src/DockComponentsFactory.cpp

@@ -17,6 +17,7 @@
 #include "DockAreaTitleBar.h"
 #include "DockWidget.h"
 #include "DockAreaWidget.h"
+#include "DockWidgetSideTab.h"
 
 namespace ads
 {
@@ -29,6 +30,12 @@ CDockWidgetTab* CDockComponentsFactory::createDockWidgetTab(CDockWidget* DockWid
 	return new CDockWidgetTab(DockWidget);
 }
 
+//============================================================================
+CDockWidgetSideTab* CDockComponentsFactory::createDockWidgetSideTab(CDockWidget *DockWidget) const
+{
+	return new CDockWidgetSideTab(DockWidget);
+}
+
 
 //============================================================================
 CDockAreaTabBar* CDockComponentsFactory::createDockAreaTabBar(CDockAreaWidget* DockArea) const

src/DockComponentsFactory.h

@@ -19,6 +19,7 @@ class CDockAreaTitleBar;
 class CDockAreaTabBar;
 class CDockAreaWidget;
 class CDockWidget;
+class CDockWidgetSideTab;
 
 
 
@@ -46,6 +47,12 @@ public:
 	 */
 	virtual CDockWidgetTab* createDockWidgetTab(CDockWidget* DockWidget) const;
 
+	/**
+	 * This default implementation just creates a dock widget side tab with
+	 * new CDockWidgetTab(DockWidget).
+	 */
+	virtual CDockWidgetSideTab* createDockWidgetSideTab(CDockWidget* DockWidget) const;
+
 	/**
 	 * This default implementation just creates a dock area tab bar with
 	 * new CDockAreaTabBar(DockArea).

src/DockContainerWidget.cpp

@@ -38,6 +38,7 @@
 #include <QDebug>
 #include <QXmlStreamWriter>
 #include <QAbstractButton>
+#include <QLabel>
 
 #include "DockManager.h"
 #include "DockAreaWidget.h"
@@ -47,6 +48,11 @@
 #include "DockOverlay.h"
 #include "ads_globals.h"
 #include "DockSplitter.h"
+#include "SideTabBar.h"
+#include "OverlayDockContainer.h"
+#include "DockWidgetTab.h"
+#include "DockWidgetSideTab.h"
+#include "DockAreaTitleBar.h"
 
 #include <functional>
 #include <iostream>
@@ -131,6 +137,7 @@ public:
 	QPointer<CDockManager> DockManager;
 	unsigned int zOrderIndex = 0;
 	QList<CDockAreaWidget*> DockAreas;
+	QMap<SideTabBarArea, CSideTabBar*> SideTabBarWidgets;
 	QGridLayout* Layout = nullptr;
 	QSplitter* RootSplitter = nullptr;
 	bool isFloating = false;
@@ -212,6 +219,11 @@ public:
 	void saveChildNodesState(QXmlStreamWriter& Stream, QWidget* Widget);
 
 	/**
+	 * Save state of overlay widgets
+	 */
+    void saveOverlayWidgetsState(QXmlStreamWriter& Stream);
+
+    /**
 	 * Restore state of child nodes.
 	 * \param[in] Stream The data stream that contains the serialized state
 	 * \param[out] CreatedWidget The widget created from parsed data or 0 if
@@ -236,6 +248,19 @@ public:
 	bool restoreDockArea(CDockingStateReader& Stream, QWidget*& CreatedWidget,
 		bool Testing);
 
+	/**
+	 * Restores the overlay dock area.
+     * Assumes that there are no overlay dock areas, and then restores all the dock areas that
+     * exist in the XML
+	 */
+    bool restoreOverlayDockArea(CDockingStateReader& s, SideTabBarArea area, bool Testing);
+
+	/**
+	 * Restores either a dock area or an overlay dock area depending on the value in the XML
+	 */
+    bool restoreDockOrOverlayDockArea(CDockingStateReader& Stream, QWidget*& CreatedWidget,
+        bool Testing);
+
 	/**
 	 * Helper function for recursive dumping of layout
 	 */
@@ -404,11 +429,13 @@ void DockContainerWidgetPrivate::onVisibleDockAreaCountChanged()
 		this->TopLevelDockArea = TopLevelDockArea;
 		TopLevelDockArea->titleBarButton(TitleBarButtonUndock)->setVisible(false || !_this->isFloating());
 		TopLevelDockArea->titleBarButton(TitleBarButtonClose)->setVisible(false || !_this->isFloating());
+		TopLevelDockArea->titleBarButton(TitleBarButtonAutoHide)->setVisible(false || !_this->isFloating());
 	}
 	else if (this->TopLevelDockArea)
 	{
 		this->TopLevelDockArea->titleBarButton(TitleBarButtonUndock)->setVisible(true);
 		this->TopLevelDockArea->titleBarButton(TitleBarButtonClose)->setVisible(true);
+		this->TopLevelDockArea->titleBarButton(TitleBarButtonAutoHide)->setVisible(true);
 		this->TopLevelDockArea = nullptr;
 	}
 }
@@ -807,6 +834,7 @@ void DockContainerWidgetPrivate::addDockAreasToList(const QList<CDockAreaWidget*
 	{
 		DockArea->titleBarButton(TitleBarButtonUndock)->setVisible(true);
 		DockArea->titleBarButton(TitleBarButtonClose)->setVisible(true);
+		DockArea->titleBarButton(TitleBarButtonAutoHide)->setVisible(true);
 	}
 
 	// We need to ensure, that the dock area title bar is visible. The title bar
@@ -873,6 +901,19 @@ void DockContainerWidgetPrivate::saveChildNodesState(QXmlStreamWriter& s, QWidge
 	}
 }
 
+void DockContainerWidgetPrivate::saveOverlayWidgetsState(QXmlStreamWriter& Stream)
+{
+    for (const auto dockAreaWidget : _this->findChildren<CDockAreaWidget*>())
+    {
+        if (!dockAreaWidget->isOverlayed())
+        {
+            continue;
+        }
+
+        dockAreaWidget->saveState(Stream);
+    }
+}
+
 
 //============================================================================
 bool DockContainerWidgetPrivate::restoreSplitter(CDockingStateReader& s,
@@ -989,6 +1030,126 @@ bool DockContainerWidgetPrivate::restoreSplitter(CDockingStateReader& s,
 	return true;
 }
 
+//============================================================================
+bool DockContainerWidgetPrivate::restoreOverlayDockArea(CDockingStateReader& s, SideTabBarArea area, bool Testing)
+{
+	bool Ok;
+#ifdef ADS_DEBUG_PRINT
+	int Tabs = s.attributes().value("Tabs").toInt(&Ok);
+	if (!Ok)
+	{
+		return false;
+	}
+#endif
+
+	QString CurrentDockWidget = s.attributes().value("Current").toString();
+    ADS_PRINT("Restore NodeDockArea Tabs: " << Tabs << " Current: "
+            << CurrentDockWidget);
+
+	if (area == Left && !CDockManager::testConfigFlag(CDockManager::DockContainerHasLeftSideBar))
+	{
+		return false;
+	}
+
+	if (area == Right && !CDockManager::testConfigFlag(CDockManager::DockContainerHasRightSideBar))
+	{
+		return false;
+	}
+
+	CDockAreaWidget* DockArea = nullptr;
+	if (!Testing)
+	{
+        const auto dockContainer = new COverlayDockContainer(DockManager, area, _this);
+		if (!dockContainer->restoreState(s, Testing))
+		{
+			return false;
+		}
+
+        dockContainer->hide();
+        DockArea = dockContainer->dockAreaWidget();
+		const auto titleBar = DockArea->titleBar();
+		QSignalBlocker blocker(titleBar);
+		titleBar->button(TitleBarButtonAutoHide)->setChecked(true);
+	}
+
+	while (s.readNextStartElement())
+	{
+        if (s.name() != QLatin1String("Widget"))
+		{
+			continue;
+		}
+
+		auto ObjectName = s.attributes().value("Name");
+		if (ObjectName.isEmpty())
+		{
+			return false;
+		}
+
+		s.skipCurrentElement();
+		CDockWidget* DockWidget = DockManager->findDockWidget(ObjectName.toString());
+		if (!DockWidget || Testing)
+		{
+			continue;
+		}
+
+        ADS_PRINT("Dock Widget found - parent " << DockWidget->parent());
+		// We hide the DockArea here to prevent the short display (the flashing)
+		// of the dock areas during application startup
+		DockArea->hide();
+		DockWidget->setToggleViewActionChecked(false);
+		DockWidget->setClosedState(true);
+		DockWidget->setProperty(internal::ClosedProperty, true);
+		DockWidget->setProperty(internal::DirtyProperty, false);
+        _this->sideTabBar(area)->insertSideTab(0, DockWidget->sideTabWidget());
+        DockWidget->sideTabWidget()->show();
+        DockWidget->toggleView(false);
+        DockArea->overlayDockContainer()->addDockWidget(DockWidget);
+	}
+
+	if (Testing)
+	{
+		return true;
+	}
+
+	if (!DockArea->dockWidgetsCount())
+	{
+		delete DockArea;
+		DockArea = nullptr;
+	}
+	else
+	{
+		DockArea->setProperty("currentDockWidget", CurrentDockWidget);
+		appendDockAreas({DockArea});
+	}
+
+	return true;
+}
+
+
+//============================================================================
+bool DockContainerWidgetPrivate::restoreDockOrOverlayDockArea(CDockingStateReader& Stream, QWidget*& CreatedWidget,
+    bool Testing)
+{
+	bool Ok;
+	const auto sideTabAreaValue = Stream.attributes().value("SideTabBarArea");
+	if (!sideTabAreaValue.isNull())
+	{
+        auto sideTabBarArea = static_cast<SideTabBarArea>(sideTabAreaValue.toInt(&Ok));
+        if (!Ok)
+        {
+            return false;
+        }
+        if (sideTabBarArea != SideTabBarArea::None)
+        {
+            return restoreOverlayDockArea(Stream, sideTabBarArea, Testing);
+        }
+	}
+
+    // If there's no SideTabBarArea value in the XML, or the value of SideTabBarArea is none, restore the dock area
+    return restoreDockArea(Stream, CreatedWidget, Testing);
+
+}
+
 
 //============================================================================
 bool DockContainerWidgetPrivate::restoreDockArea(CDockingStateReader& s,
@@ -1054,7 +1215,7 @@ bool DockContainerWidgetPrivate::restoreDockArea(CDockingStateReader& s,
 		// We hide the DockArea here to prevent the short display (the flashing)
 		// of the dock areas during application startup
 		DockArea->hide();
-		DockArea->addDockWidget(DockWidget);
+        DockArea->addDockWidget(DockWidget);
 		DockWidget->setToggleViewActionChecked(!Closed);
 		DockWidget->setClosedState(Closed);
 		DockWidget->setProperty(internal::ClosedProperty, Closed);
@@ -1096,7 +1257,7 @@ bool DockContainerWidgetPrivate::restoreChildNodes(CDockingStateReader& s,
 		}
         else if (s.name() == QLatin1String("Area"))
 		{
-			Result = restoreDockArea(s, CreatedWidget, Testing);
+			Result = restoreDockOrOverlayDockArea(s, CreatedWidget, Testing);
             ADS_PRINT("DockAreaWidget");
 		}
 		else
@@ -1288,6 +1449,7 @@ CDockContainerWidget::CDockContainerWidget(CDockManager* DockManager, QWidget *p
 	d->Layout = new QGridLayout();
 	d->Layout->setContentsMargins(0, 0, 0, 0);
 	d->Layout->setSpacing(0);
+	d->Layout->setColumnStretch(1, 1);
 	setLayout(d->Layout);
 
 	// The function d->newSplitter() accesses the config flags from dock
@@ -1299,6 +1461,7 @@ CDockContainerWidget::CDockContainerWidget(CDockManager* DockManager, QWidget *p
 	{
 		d->DockManager->registerDockContainer(this);
 		createRootSplitter();
+		createSideTabBarWidgets();
 	}
 }
 
@@ -1334,6 +1497,45 @@ CDockAreaWidget* CDockContainerWidget::addDockWidget(DockWidgetArea area, CDockW
 	}
 }
 
+void CDockContainerWidget::createDockWidgetOverlayContainer(SideTabBarArea area, CDockWidget* DockWidget)
+{
+	if (d->DockManager != DockWidget->dockManager())
+	{
+        DockWidget->setDockManager(d->DockManager); // Overlay Dock Container needs a valid dock manager
+	}
+	const auto dockContainer = new COverlayDockContainer(DockWidget, area);
+	dockContainer->hide();
+}
+
+//============================================================================
+SideTabBarArea CDockContainerWidget::getDockAreaPosition(CDockAreaWidget* DockAreaWidget)
+{
+	const auto dockWidgetCenter = DockAreaWidget->mapToGlobal(DockAreaWidget->frameGeometry().center());
+	const auto splitterCenter = rootSplitter()->mapToGlobal(rootSplitter()->frameGeometry().center());
+	const auto calculatedPosition = dockWidgetCenter.x() <= splitterCenter.x() ? Left : Right;
+	if (calculatedPosition == Right)
+	{
+        if (CDockManager::testConfigFlag(CDockManager::DockContainerHasRightSideBar))
+        {
+            return Right;
+        }
+
+		return Left;
+	}
+
+    if (calculatedPosition == Left)
+	{
+		if (CDockManager::testConfigFlag(CDockManager::DockContainerHasLeftSideBar))
+		{
+            return Left;
+		}
+		return Right;
+	}
+
+	return Left;
+
+}
+
 //============================================================================
 void CDockContainerWidget::removeDockWidget(CDockWidget* Dockwidget)
 {
@@ -1408,6 +1610,22 @@ void CDockContainerWidget::removeDockArea(CDockAreaWidget* area)
 		*p = nullptr;
 	}
 
+	if (area->isOverlayed())
+	{
+		// Removing an area from an overlay widget implies deleting the whole overlay widget
+		// So cleanup will be done when the overlay widget is deleted
+		// Note: there is no parent splitter
+        CDockWidget* TopLevelWidget = topLevelDockWidget();
+
+        // Updated the title bar visibility of the dock widget if there is only
+        // one single visible dock widget
+        CDockWidget::emitTopLevelEventForWidget(TopLevelWidget, true);
+        dumpLayout();
+        d->emitDockAreasRemoved();
+        area->setOverlayDockContainer(nullptr);
+		return;
+	}
+
 	// If splitter has more than 1 widgets, we are finished and can leave
 	if (Splitter->count() >  1)
 	{
@@ -1675,6 +1893,7 @@ void CDockContainerWidget::saveState(QXmlStreamWriter& s) const
 #endif
 	}
 	d->saveChildNodesState(s, d->RootSplitter);
+	d->saveOverlayWidgetsState(s);
 	s.writeEndElement();
 }
 
@@ -1759,7 +1978,24 @@ void CDockContainerWidget::createRootSplitter()
 		return;
 	}
 	d->RootSplitter = d->newSplitter(Qt::Horizontal);
-	d->Layout->addWidget(d->RootSplitter);
+	d->Layout->addWidget(d->RootSplitter, 0, 1); // Add it to the center - the 0 and 2 indexes are used for the SideTabBar widgets
+}
+
+
+//============================================================================
+void CDockContainerWidget::createSideTabBarWidgets()
+{
+	if (CDockManager::testConfigFlag(CDockManager::DockContainerHasLeftSideBar))
+	{
+        d->SideTabBarWidgets[SideTabBarArea::Left] = new CSideTabBar(this);
+        d->Layout->addWidget(d->SideTabBarWidgets[SideTabBarArea::Left], 0, 0);
+	}
+
+	if (CDockManager::testConfigFlag(CDockManager::DockContainerHasRightSideBar))
+	{
+        d->SideTabBarWidgets[SideTabBarArea::Right] = new CSideTabBar(this);
+        d->Layout->addWidget(d->SideTabBarWidgets[SideTabBarArea::Right], 0, 2);
+	}
 }
 
 
@@ -1894,7 +2130,11 @@ void CDockContainerWidget::closeOtherAreas(CDockAreaWidget* KeepOpenArea)
 	}
 }
 
-
+//============================================================================
+CSideTabBar* CDockContainerWidget::sideTabBar(SideTabBarArea area) const
+{
+	return d->SideTabBarWidgets[area];
+}
 } // namespace ads
 
 //---------------------------------------------------------------------------

src/DockContainerWidget.h

@@ -50,6 +50,7 @@ struct FloatingDockContainerPrivate;
 class CFloatingDragPreview;
 struct FloatingDragPreviewPrivate;
 class CDockingStateReader;
+class CSideTabBar;
 
 
 /**
@@ -74,6 +75,7 @@ private:
 	friend class CDockWidget;
 	friend class CFloatingDragPreview;
 	friend struct FloatingDragPreviewPrivate;
+	friend class COverlayDockContainer;
 
 protected:
 	/**
@@ -91,6 +93,11 @@ protected:
 	 */
 	void createRootSplitter();
 
+	/**
+	 * Helper function for creation of the side tab bar widgets
+	 */
+	void createSideTabBarWidgets();
+
 	/**
 	 * Drop floating widget into the container
 	 */
@@ -163,6 +170,7 @@ protected:
     void updateSplitterHandles(QSplitter* splitter);
 
 public:
+
 	/**
 	 * Default Constructor
 	 */
@@ -183,6 +191,16 @@ public:
 	CDockAreaWidget* addDockWidget(DockWidgetArea area, CDockWidget* Dockwidget,
 		CDockAreaWidget* DockAreaWidget = nullptr);
 
+	/**
+	 * Creates and adds a dockwidget overlay container into the given area.
+	 */
+	void createDockWidgetOverlayContainer(SideTabBarArea area, CDockWidget* DockWidget);
+
+	/**
+	 * Get's the overlay dock side tab bar area based on the dock area widget position
+	 */
+	SideTabBarArea getDockAreaPosition(CDockAreaWidget* DockAreaWidget);
+
 	/**
 	 * Removes dockwidget
 	 */
@@ -278,6 +296,11 @@ public:
 	 */
 	void closeOtherAreas(CDockAreaWidget* KeepOpenArea);
 
+	/**
+	 * Returns the side tab widget for the given area
+	 */
+	CSideTabBar* sideTabBar(SideTabBarArea area) const;
+
 Q_SIGNALS:
 	/**
 	 * This signal is emitted if one or multiple dock areas has been added to

src/DockFocusController.cpp

@@ -25,6 +25,8 @@
 #include "FloatingDockContainer.h"
 #include "DockManager.h"
 #include "DockAreaTitleBar.h"
+#include "DockWidgetSideTab.h"
+#include "OverlayDockContainer.h"
 
 #ifdef Q_OS_LINUX
 #include "linux/FloatingWidgetTitleBar.h"
@@ -69,6 +71,8 @@ static void updateDockWidgetFocusStyle(CDockWidget* DockWidget, bool Focused)
 	DockWidget->setProperty("focused", Focused);
 	DockWidget->tabWidget()->setProperty("focused", Focused);
 	DockWidget->tabWidget()->updateStyle();
+	DockWidget->sideTabWidget()->setProperty("focused", Focused);
+	DockWidget->sideTabWidget()->updateStyle();
 	internal::repolishStyle(DockWidget);
 }
 
@@ -185,6 +189,11 @@ void DockFocusControllerPrivate::updateDockWidgetFocus(CDockWidget* DockWidget)
 	}
 #endif
 
+	if (old && old->overlayDockContainer() && old != DockWidget)
+	{
+		old->overlayDockContainer()->hide();
+	}
+
     if (old == DockWidget && !ForceFocusChangedSignal)
     {
     	return;

src/DockManager.cpp

@@ -56,6 +56,7 @@
 #include "DockAreaTitleBar.h"
 #include "DockFocusController.h"
 #include "DockSplitter.h"
+#include "OverlayDockContainer.h"
 
 #ifdef Q_OS_LINUX
 #include "linux/FloatingWidgetTitleBar.h"
@@ -99,6 +100,7 @@ struct DockManagerPrivate
 	CDockManager* _this;
 	QList<CFloatingDockContainer*> FloatingWidgets;
 	QList<CFloatingDockContainer*> HiddenFloatingWidgets;
+	QList<COverlayDockContainer*> OverlayWidgets;
 	QList<CDockContainerWidget*> Containers;
 	CDockOverlay* ContainerOverlay;
 	CDockOverlay* DockAreaOverlay;
@@ -146,6 +148,15 @@ struct DockManagerPrivate
 		}
 	}
 
+	void deleteOverlayWidgets()
+	{
+	    for (auto OverlayWidget : OverlayWidgets)
+	    {
+			OverlayWidget->cleanupAndDelete();
+	    }
+		OverlayWidgets.clear();
+	}
+
 	void markDockWidgetsDirty()
 	{
 		for (auto DockWidget : DockWidgetsMap)
@@ -430,6 +441,7 @@ bool DockManagerPrivate::restoreState(const QByteArray& State, int version)
 
     // Hide updates of floating widgets from use
     hideFloatingWidgets();
+	deleteOverlayWidgets();
     markDockWidgetsDirty();
 
     if (!restoreStateFromXml(state, version))
@@ -481,6 +493,7 @@ CDockManager::CDockManager(QWidget *parent) :
 	d(new DockManagerPrivate(this))
 {
 	createRootSplitter();
+	createSideTabBarWidgets();
 	QMainWindow* MainWindow = qobject_cast<QMainWindow*>(parent);
 	if (MainWindow)
 	{
@@ -525,6 +538,13 @@ CDockManager::~CDockManager()
 	{
 		delete FloatingWidget;
 	}
+
+	auto OverlayWidgets = d->OverlayWidgets;
+	for (auto OverlayWidget : OverlayWidgets)
+	{
+		delete OverlayWidget;
+	}
+
 	delete d;
 }
 
@@ -616,6 +636,14 @@ void CDockManager::registerFloatingWidget(CFloatingDockContainer* FloatingWidget
     ADS_PRINT("d->FloatingWidgets.count() " << d->FloatingWidgets.count());
 }
 
+//============================================================================
+void CDockManager::registerOverlayWidget(COverlayDockContainer* OverlayWidget)
+{
+	d->OverlayWidgets.append(OverlayWidget);
+	Q_EMIT overlayWidgetCreated(OverlayWidget);
+    ADS_PRINT("d->OverlayWidgets.count() " << d->OverlayWidgets.count());
+}
+
 
 //============================================================================
 void CDockManager::removeFloatingWidget(CFloatingDockContainer* FloatingWidget)
@@ -623,6 +651,11 @@ void CDockManager::removeFloatingWidget(CFloatingDockContainer* FloatingWidget)
 	d->FloatingWidgets.removeAll(FloatingWidget);
 }
 
+//============================================================================
+void CDockManager::removeOverlayWidget(COverlayDockContainer* OverlayWidget)
+{
+	d->OverlayWidgets.removeAll(OverlayWidget);
+}
 
 //============================================================================
 void CDockManager::registerDockContainer(CDockContainerWidget* DockContainer)

src/DockManager.h

@@ -84,6 +84,7 @@ private:
 	friend class CFloatingDragPreview;
 	friend struct FloatingDragPreviewPrivate;
 	friend class CDockAreaTitleBar;
+	friend class COverlayDockContainer;
 
 
 protected:
@@ -93,12 +94,24 @@ protected:
 	 */
 	void registerFloatingWidget(CFloatingDockContainer* FloatingWidget);
 
+	/**
+	 * Registers the given floating widget in the internal list of
+	 * overlay widgets
+	 */
+    void registerOverlayWidget(COverlayDockContainer* OverlayWidget);
+
 	/**
 	 * Remove the given floating widget from the list of registered floating
 	 * widgets
 	 */
 	void removeFloatingWidget(CFloatingDockContainer* FloatingWidget);
 
+    /**
+	 * Remove the given overlay widget from the list of registered overlay
+	 * widgets
+	 */
+    void removeOverlayWidget(COverlayDockContainer* OverlayWidget);
+
 	/**
 	 * Registers the given dock container widget
 	 */
@@ -202,14 +215,24 @@ public:
 														 //! Users can overwrite this by setting the environment variable ADS_UseNativeTitle to "1" or "0".
 		MiddleMouseButtonClosesTab = 0x2000000, //! If the flag is set, the user can use the mouse middle button to close the tab under the mouse
 
+		DockAreaHasAutoHideButton = 0x4000000,     //!< If the flag is set each dock area has a auto hide menu button
+		DockContainerHasLeftSideBar = 0x8000000,     //!< If the flag is set each container will have a left side bar
+		DockContainerHasRightSideBar = 0x10000000,     //!< If the flag is set each container will have a right side bar
+
+
         DefaultDockAreaButtons = DockAreaHasCloseButton
 							   | DockAreaHasUndockButton
-		                       | DockAreaHasTabsMenuButton,///< default configuration of dock area title bar buttons
+		                       | DockAreaHasTabsMenuButton
+	                           | DockAreaHasAutoHideButton,///< default configuration of dock area title bar buttons
+
+		DefaultDockContainerSideBars = DockContainerHasLeftSideBar 
+	                                 | DockContainerHasRightSideBar, ///< the default configuration for left and right side bars
 
 		DefaultBaseConfig = DefaultDockAreaButtons
 		                  | ActiveTabHasCloseButton
 		                  | XmlCompressionEnabled
-		                  | FloatingContainerHasWidgetTitle,///< default base configuration settings
+		                  | FloatingContainerHasWidgetTitle
+	                      | DefaultDockContainerSideBars, ///< default base configuration settings
 
         DefaultOpaqueConfig = DefaultBaseConfig
 		                    | OpaqueSplitterResize
@@ -602,6 +625,11 @@ Q_SIGNALS:
 	 */
 	void floatingWidgetCreated(ads::CFloatingDockContainer* FloatingWidget);
 
+	/**
+	 * This signal is emitted, if a new overlay widget has been created.
+	 */
+	void overlayWidgetCreated(ads::COverlayDockContainer* OverlayWidget);
+
     /**
      * This signal is emitted, if a new DockArea has been created.
      * An application can use this signal to set custom icons or custom

src/DockWidget.cpp

@@ -50,6 +50,8 @@
 #include <QScreen>
 #include <QWindow>
 
+#include "SideTabBar.h"
+#include "DockWidgetSideTab.h"
 #include "DockContainerWidget.h"
 #include "DockAreaWidget.h"
 #include "DockManager.h"
@@ -57,6 +59,7 @@
 #include "DockSplitter.h"
 #include "DockComponentsFactory.h"
 #include "ads_globals.h"
+#include "OverlayDockContainer.h"
 
 
 namespace ads
@@ -76,6 +79,7 @@ struct DockWidgetPrivate
 	QBoxLayout* Layout = nullptr;
 	QWidget* Widget = nullptr;
 	CDockWidgetTab* TabWidget = nullptr;
+	CDockWidgetSideTab* SideTabWidget = nullptr;
 	CDockWidget::DockWidgetFeatures Features = CDockWidget::DefaultDockWidgetFeatures;
 	CDockManager* DockManager = nullptr;
 	CDockAreaWidget* DockArea = nullptr;
@@ -182,6 +186,11 @@ void DockWidgetPrivate::showDockWidget()
 					CFloatingDockContainer*>(Container);
 			FloatingWidget->show();
 		}
+
+		if (DockArea->isOverlayed())
+		{
+			DockArea->overlayDockContainer()->show();
+		}
 	}
 }
 
@@ -197,6 +206,11 @@ void DockWidgetPrivate::hideDockWidget()
 		Widget->deleteLater();
 		Widget = nullptr;
 	}
+
+	if (DockArea->isOverlayed())
+	{
+		DockArea->overlayDockContainer()->hide();
+	}
 }
 
 
@@ -287,7 +301,11 @@ CDockWidget::CDockWidget(const QString &title, QWidget *parent) :
 	setObjectName(title);
 
 	d->TabWidget = componentsFactory()->createDockWidgetTab(this);
-    d->ToggleViewAction = new QAction(title, this);
+	d->SideTabWidget = componentsFactory()->createDockWidgetSideTab(this);
+
+	connect(d->SideTabWidget, &CDockWidgetSideTab::clicked, this, &CDockWidget::onDockWidgetSideTabClicked);
+
+	d->ToggleViewAction = new QAction(title, this);
 	d->ToggleViewAction->setCheckable(true);
 	connect(d->ToggleViewAction, SIGNAL(triggered(bool)), this,
 		SLOT(toggleView(bool)));
@@ -302,7 +320,7 @@ CDockWidget::CDockWidget(const QString &title, QWidget *parent) :
 //============================================================================
 CDockWidget::~CDockWidget()
 {
-    ADS_PRINT("~CDockWidget()");
+	ADS_PRINT("~CDockWidget()");
 	delete d;
 }
 
@@ -379,7 +397,7 @@ QWidget* CDockWidget::takeWidget()
 	{
 		w->setParent(nullptr);
 	}
-    return w;
+	return w;
 }
 
 
@@ -396,6 +414,16 @@ CDockWidgetTab* CDockWidget::tabWidget() const
 	return d->TabWidget;
 }
 
+COverlayDockContainer* CDockWidget::overlayDockContainer() const
+{
+	if (!d->DockArea)
+	{
+		return nullptr;
+	}
+
+	return d->DockArea->overlayDockContainer();
+}
+
 
 //============================================================================
 void CDockWidget::setFeatures(DockWidgetFeatures features)
@@ -416,8 +444,8 @@ void CDockWidget::setFeatures(DockWidgetFeatures features)
 void CDockWidget::setFeature(DockWidgetFeature flag, bool on)
 {
 	auto Features = features();
-    internal::setFlag(Features, flag, on);
+	internal::setFlag(Features, flag, on);
-    setFeatures(Features);
+	setFeatures(Features);
 }
 
 
@@ -470,6 +498,12 @@ CDockAreaWidget* CDockWidget::dockAreaWidget() const
 	return d->DockArea;
 }
 
+//============================================================================
+CDockWidgetSideTab* CDockWidget::sideTabWidget() const
+{
+	return d->SideTabWidget;
+}
+
 
 //============================================================================
 bool CDockWidget::isFloating() const
@@ -541,7 +575,7 @@ void CDockWidget::setMinimumSizeHintMode(eMinimumSizeHintMode Mode)
 //============================================================================
 bool CDockWidget::isCentralWidget() const
 {
-    return dockManager()->centralWidget() == this;
+	return dockManager()->centralWidget() == this;
 }
 
 
@@ -662,7 +696,7 @@ bool CDockWidget::event(QEvent *e)
 
 	case QEvent::Show:
 		Q_EMIT visibilityChanged(geometry().right() >= 0 && geometry().bottom() >= 0);
-        break;
+		break;
 
 	case QEvent::WindowTitleChange :
 		{
@@ -938,7 +972,7 @@ bool CDockWidget::closeDockWidgetInternal(bool ForceClose)
 	}
 
 	if (features().testFlag(CDockWidget::DockWidgetDeleteOnClose))
-    {
+	{
 		// If the dock widget is floating, then we check if we also need to
 		// delete the floating widget
 		if (isFloating())
@@ -956,11 +990,11 @@ bool CDockWidget::closeDockWidgetInternal(bool ForceClose)
 		}
 		deleteDockWidget();
 		Q_EMIT closed();
-    }
+	}
-    else
+	else
-    {
+	{
-    	toggleView(false);
+		toggleView(false);
-    }
+	}
 
 	return true;
 }
@@ -1007,6 +1041,27 @@ void CDockWidget::showNormal()
 	}
 }
 
+//============================================================================
+void CDockWidget::onDockWidgetSideTabClicked()
+{
+	const auto overlayContainer = overlayDockContainer();
+	if (!overlayContainer)
+	{
+		return;
+	}
+
+	overlayContainer->raise();
+	const auto show = !overlayContainer->isVisible();
+	overlayContainer->setVisible(show);
+	toggleView(show);
+	if (overlayContainer->isVisible())
+	{
+		// d->DockManager->setDockWidgetFocused(this) does not
+		// de focus the old widget, leading to the overlay still being visible
+		// even after clicking outside the overlay.
+		setFocus(Qt::ActiveWindowFocusReason);
+	}
+}
 
 //============================================================================
 bool CDockWidget::isFullScreen() const

src/DockWidget.h

@@ -46,6 +46,8 @@ class CDockContainerWidget;
 class CDockAreaWidget;
 class DockContainerWidgetPrivate;
 class CFloatingDockContainer;
+class CDockWidgetSideTab;
+class COverlayDockContainer;
 
 /**
  * The QDockWidget class provides a widget that can be docked inside a
@@ -75,6 +77,7 @@ protected:
     friend class CDockWidgetTab;
     friend struct DockWidgetTabPrivate;
     friend struct DockAreaTitleBarPrivate;
+    friend class COverlayDockContainer;
 
     /**
      * Assigns the dock manager that manages this dock widget
@@ -300,6 +303,12 @@ public:
      */
     CDockWidgetTab* tabWidget() const;
 
+    /**
+     * Returns the overlay dock container of this dock widget 
+     * or 0 if there is none
+     */
+    COverlayDockContainer* overlayDockContainer() const;
+
     /**
      * Sets, whether the dock widget is movable, closable, and floatable.
      */
@@ -343,6 +352,11 @@ public:
      */
     CDockAreaWidget* dockAreaWidget() const;
 
+    /**
+     * Returns the side tab widget for this dock
+     */
+    CDockWidgetSideTab* sideTabWidget() const;
+
     /**
      * This property holds whether the dock widget is floating.
      * A dock widget is only floating, if it is the one and only widget inside
@@ -563,6 +577,10 @@ public Q_SLOTS:
      */
     void showNormal();
 
+    /**
+     * Shows the dock overlay container when the side tab is clicked
+     */
+    void onDockWidgetSideTabClicked();
 
 Q_SIGNALS:
     /**

src/DockWidgetSideTab.cpp

@@ -0,0 +1,151 @@
+/*******************************************************************************
+** Qt Advanced Docking System
+** Copyright (C) 2017 Uwe Kindler
+**
+** This library is free software; you can redistribute it and/or
+** modify it under the terms of the GNU Lesser General Public
+** License as published by the Free Software Foundation; either
+** version 2.1 of the License, or (at your option) any later version.
+**
+** This library is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+** Lesser General Public License for more details.
+**
+** You should have received a copy of the GNU Lesser General Public
+** License along with this library; If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+
+//============================================================================
+/// \file   DockWidgetTab.h
+/// \author Syarif Fakhri
+/// \date   05.09.2022
+/// \brief  Implementation of CDockWidgetSideTab class
+//============================================================================
+
+//============================================================================
+//                                   INCLUDES
+//============================================================================
+#include "DockWidgetSideTab.h"
+#include "SideTabBar.h"
+
+#include <QBoxLayout>
+
+#include "ElidingLabel.h"
+
+#include "DockWidget.h"
+
+namespace ads
+{
+
+using tTabLabel = CVerticalElidingLabel;
+
+/**
+ * Private data class of CDockWidgetTab class (pimpl)
+ */
+struct DockWidgetSideTabPrivate
+{
+    CDockWidgetSideTab* _this;
+    CDockWidget* DockWidget;
+    tTabLabel* TitleLabel;
+	QBoxLayout* Layout;
+	CSideTabBar* SideTabBar;
+
+	/**
+	 * Private data constructor
+	 */
+	DockWidgetSideTabPrivate(CDockWidgetSideTab* _public);
+
+	/**
+	 * Creates the complete layout
+	 */
+	void createLayout();
+};
+// struct DockWidgetTabPrivate
+
+
+//============================================================================
+DockWidgetSideTabPrivate::DockWidgetSideTabPrivate(CDockWidgetSideTab* _public) :
+	_this(_public)
+{
+
+}
+
+//============================================================================
+void DockWidgetSideTabPrivate::createLayout()
+{
+	TitleLabel = new tTabLabel();
+	TitleLabel->setElideMode(Qt::ElideRight);
+	TitleLabel->setText(DockWidget->windowTitle());
+	TitleLabel->setObjectName("dockWidgetTabLabel");
+	TitleLabel->setAlignment(Qt::AlignCenter);
+	_this->connect(TitleLabel, SIGNAL(elidedChanged(bool)), SIGNAL(elidedChanged(bool)));
+
+	QFontMetrics fm(TitleLabel->font());
+	int Spacing = qRound(fm.height() / 2.0);
+
+	// Fill the layout
+	Layout = new QBoxLayout(QBoxLayout::LeftToRight);
+	Layout->setContentsMargins(Spacing,Spacing,0,Spacing);
+	Layout->setSpacing(0);
+	_this->setLayout(Layout);
+	Layout->addWidget(TitleLabel, 1);
+	Layout->setAlignment(Qt::AlignCenter);
+
+	TitleLabel->setVisible(true);
+}
+
+//============================================================================
+void CDockWidgetSideTab::mousePressEvent(QMouseEvent* event)
+{
+	if (event->button() == Qt::LeftButton)
+	{
+        emit clicked();
+	}
+
+    QFrame::mousePressEvent(event);
+}
+
+
+//============================================================================
+void CDockWidgetSideTab::setSideTabBar(CSideTabBar* SideTabBar)
+{
+	d->SideTabBar = SideTabBar;
+}
+
+
+//============================================================================
+void CDockWidgetSideTab::removeFromSideTabBar()
+{
+	if (d->SideTabBar == nullptr)
+	{
+		return;
+	}
+	d->SideTabBar->removeSideTab(this);
+    setSideTabBar(nullptr);
+}
+
+//============================================================================
+CDockWidgetSideTab::CDockWidgetSideTab(CDockWidget* DockWidget, QWidget* parent) : 
+	QFrame(parent),
+	d(new DockWidgetSideTabPrivate(this))
+{
+	setAttribute(Qt::WA_NoMousePropagation);
+	d->DockWidget = DockWidget;
+	d->createLayout();
+	setFocusPolicy(Qt::NoFocus);
+}
+
+//============================================================================
+CDockWidgetSideTab::~CDockWidgetSideTab()
+{
+	delete d;
+}
+
+//============================================================================
+void CDockWidgetSideTab::updateStyle()
+{
+	internal::repolishStyle(this, internal::RepolishDirectChildren);
+}
+}

src/DockWidgetSideTab.h

@@ -0,0 +1,96 @@
+#ifndef DockWidgetSideTabH
+#define DockWidgetSideTabH
+/*******************************************************************************
+** Qt Advanced Docking System
+** Copyright (C) 2017 Uwe Kindler
+**
+** This library is free software; you can redistribute it and/or
+** modify it under the terms of the GNU Lesser General Public
+** License as published by the Free Software Foundation; either
+** version 2.1 of the License, or (at your option) any later version.
+**
+** This library is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+** Lesser General Public License for more details.
+**
+** You should have received a copy of the GNU Lesser General Public
+** License along with this library; If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+
+//============================================================================
+/// \file   DockWidgetTab.h
+/// \author Syarif Fakhri
+/// \date   05.09.2022
+/// \brief  Declaration of CDockWidgetSideTab class
+//============================================================================
+
+//============================================================================
+//                                   INCLUDES
+//============================================================================
+#include <QFrame>
+
+#include "ads_globals.h"
+
+namespace ads
+{
+struct DockWidgetSideTabPrivate;
+class CDockWidget;
+class CSideTabBar;
+class CDockWidgetTab;
+
+/**
+ * A dock widget Side tab that shows a title or an icon.
+ * The dock widget tab is shown in the side tab bar to switch between
+ * pinned dock widgets
+ */
+class ADS_EXPORT CDockWidgetSideTab : public QFrame
+{
+    Q_OBJECT
+
+private:    
+	DockWidgetSideTabPrivate* d; ///< private data (pimpl)
+    friend struct DockWidgetSideTabPrivate;
+	friend class CDockWidget;
+	friend class COverlayDockContainer;
+
+protected:
+	friend class CSideTabBar;
+	friend class CDockAreaWidget;
+	friend class CDockContainerWidget;
+
+	void mousePressEvent(QMouseEvent* event) override;
+
+	void setSideTabBar(CSideTabBar *SideTabBar);
+	void removeFromSideTabBar();
+
+public:
+    using Super = QFrame;
+	/**
+	 * Default Constructor
+	 * param[in] DockWidget The dock widget this title bar belongs to
+	 * param[in] Orientation Horizontal or vertical orientation
+	 * param[in] parent The parent widget of this title bar
+	 */
+	CDockWidgetSideTab(CDockWidget* DockWidget, QWidget* parent = nullptr);
+
+	/**
+	 * Virtual Destructor
+	 */
+	virtual ~CDockWidgetSideTab();
+
+	/**
+	 * Update stylesheet style if a property changes
+	 */
+	void updateStyle();
+
+Q_SIGNALS:
+	void elidedChanged(bool elided);
+	void clicked();
+}; // class DockWidgetSideTab
+}
+ // namespace ads
+//-----------------------------------------------------------------------------
+
+#endif

src/DockWidgetTab.cpp

@@ -51,6 +51,7 @@
 #include "DockManager.h"
 #include "IconProvider.h"
 #include "DockFocusController.h"
+#include "OverlayDockContainer.h"
 
 
 namespace ads
@@ -752,7 +753,6 @@ QSize CDockWidgetTab::iconSize() const
 	return d->IconSize;
 }
 
-
 //============================================================================
 void CDockWidgetTab::setIconSize(const QSize& Size)
 {

src/DockWidgetTab.h

@@ -58,6 +58,7 @@ private:
 	friend struct DockWidgetTabPrivate;
 	friend class CDockWidget;
 	friend class CDockManager;
+	friend class COverlayDockContainer;
 	void onDockWidgetFeaturesChanged();
 
 private Q_SLOTS:

src/ElidingLabel.cpp

@@ -29,6 +29,7 @@
 //============================================================================
 #include "ElidingLabel.h"
 #include <QMouseEvent>
+#include <QPainter>
 
 
 namespace ads
@@ -225,6 +226,34 @@ QString CElidingLabel::text() const
 {
 	return d->Text;
 }
+
+//============================================================================
+CVerticalElidingLabel::CVerticalElidingLabel(QWidget* parent, Qt::WindowFlags f) :
+	CElidingLabel(parent, f)
+{
+}
+
+//============================================================================
+void CVerticalElidingLabel::paintEvent(QPaintEvent* event)
+{
+	QPainter painter(this);
+	painter.rotate(90);
+	painter.drawText(0,0, text());
+}
+
+//============================================================================
+QSize CVerticalElidingLabel::sizeHint() const
+{
+	QSize s = CElidingLabel::minimumSizeHint();
+	return QSize(s.height(), s.width());
+}
+
+//============================================================================
+QSize CVerticalElidingLabel::minimumSizeHint() const
+{
+	QSize s = CElidingLabel::sizeHint();
+	return QSize(s.height(), s.width());
+}
 } // namespace QtLabb
 
 //---------------------------------------------------------------------------

src/ElidingLabel.h

@@ -102,6 +102,18 @@ Q_SIGNALS:
 	void elidedChanged(bool elided);
 }; //class CElidingLabel
 
+
+class CVerticalElidingLabel : public CElidingLabel
+{
+protected:
+	void paintEvent(QPaintEvent* event) override;
+	QSize sizeHint() const override;
+	QSize minimumSizeHint() const override;
+
+public:
+	CVerticalElidingLabel(QWidget* parent = 0, Qt::WindowFlags f = Qt::WindowFlags ());
+}; // class CVerticalElidingLabel
+
 } // namespace QtLabb
 
 //---------------------------------------------------------------------------

src/FloatingDragPreview.cpp

@@ -21,6 +21,7 @@
 #include "DockManager.h"
 #include "DockContainerWidget.h"
 #include "DockOverlay.h"
+#include "OverlayDockContainer.h"
 
 namespace ads
 {
@@ -319,6 +320,9 @@ void CFloatingDragPreview::startFloating(const QPoint &DragStartMousePos,
 void CFloatingDragPreview::finishDragging()
 {
 	ADS_PRINT("CFloatingDragPreview::finishDragging");
+
+	cleanupOverlayContainerWidget();
+
 	auto DockDropArea = d->DockManager->dockAreaOverlay()->visibleDropAreaUnderCursor();
 	auto ContainerDropArea = d->DockManager->containerOverlay()->visibleDropAreaUnderCursor();
 	if (!d->DropContainer)
@@ -353,6 +357,22 @@ void CFloatingDragPreview::finishDragging()
 }
 
 
+//============================================================================
+void CFloatingDragPreview::cleanupOverlayContainerWidget()
+{
+	auto DroppedDockWidget = qobject_cast<CDockWidget*>(d->Content);
+	auto DroppedArea = qobject_cast<CDockAreaWidget*>(d->Content);
+	if (DroppedDockWidget && DroppedDockWidget->overlayDockContainer())
+	{
+		DroppedDockWidget->overlayDockContainer()->cleanupAndDelete();
+	}
+	if (DroppedArea && DroppedArea->overlayDockContainer())
+	{
+		DroppedArea->overlayDockContainer()->cleanupAndDelete();
+	}
+}
+
+
 //============================================================================
 void CFloatingDragPreview::paintEvent(QPaintEvent* event)
 {

src/FloatingDragPreview.h

@@ -92,6 +92,11 @@ public: // implements IFloatingWidget -----------------------------------------
 	 */
 	virtual void finishDragging() override;
 
+	/**
+	 * Cleanup overlay container if the dragged widget has one
+	 */
+	void cleanupOverlayContainerWidget();
+
 Q_SIGNALS:
 	/**
 	 * This signal is emitted, if dragging has been canceled by escape key

src/OverlayDockContainer.cpp

@@ -0,0 +1,309 @@
+/*******************************************************************************
+** Qt Advanced Docking System
+** Copyright (C) 2017 Uwe Kindler
+**
+** This library is free software; you can redistribute it and/or
+** modify it under the terms of the GNU Lesser General Public
+** License as published by the Free Software Foundation; either
+** version 2.1 of the License, or (at your option) any later version.
+**
+** This library is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+** Lesser General Public License for more details.
+**
+** You should have received a copy of the GNU Lesser General Public
+** License along with this library; If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+
+//============================================================================
+/// \file   DockWidgetTab.h
+/// \author Syarif Fakhri
+/// \date   05.09.2022
+/// \brief  Implementation of COverlayDockContainer class
+//============================================================================
+
+//============================================================================
+//                                   INCLUDES
+//============================================================================
+#include "OverlayDockContainer.h"
+#include "DockManager.h"
+#include "DockWidgetSideTab.h"
+#include "DockWidgetTab.h"
+#include "SideTabBar.h"
+#include "DockAreaTitleBar.h"
+#include "DockAreaWidget.h"
+#include "DockingStateReader.h"
+
+#include <QXmlStreamWriter>
+#include <QAbstractButton>
+#include <QBoxLayout>
+#include <QPainter>
+#include <QSplitter>
+
+namespace ads
+{
+struct OverlayDockContainerPrivate
+{
+    COverlayDockContainer* _this;
+	CDockAreaWidget* DockArea{nullptr};
+	CDockWidget* DockWidget{nullptr};
+	QPointer<CDockManager> DockManager{nullptr};
+	QSplitter* Splitter;
+	SideTabBarArea Area;
+
+	/**
+	 * Private data constructor
+	 */
+	OverlayDockContainerPrivate(COverlayDockContainer *_public);
+}; // struct OverlayDockContainerPrivate
+
+//============================================================================
+OverlayDockContainerPrivate::OverlayDockContainerPrivate(
+    COverlayDockContainer *_public) :
+	_this(_public)
+{
+
+}
+
+CDockContainerWidget* COverlayDockContainer::parentContainer() const
+{
+	return qobject_cast<CDockContainerWidget*>(parent());
+}
+
+//============================================================================
+COverlayDockContainer::COverlayDockContainer(CDockManager* DockManager, SideTabBarArea area, CDockContainerWidget* parent) :
+    QFrame(parent),
+    d(new OverlayDockContainerPrivate(this))
+{
+	d->DockManager = DockManager;
+	d->Area = area;
+	d->DockArea = new CDockAreaWidget(DockManager, parent);
+	d->DockArea->setObjectName("OverlayDockArea");
+	d->DockArea->setOverlayDockContainer(this);
+	auto autoHideButton = d->DockArea->titleBar()->button(TitleBarButtonAutoHide);
+	autoHideButton->blockSignals(true);
+	autoHideButton->setChecked(true);
+	autoHideButton->blockSignals(false);
+
+	QBoxLayout* l = new QBoxLayout(QBoxLayout::LeftToRight);
+	d->Splitter = new QSplitter(Qt::Orientation::Horizontal);
+	d->Splitter->setChildrenCollapsible(false);
+
+	const auto emptyWidget = new QWidget();
+	emptyWidget->setMinimumWidth(50);
+
+	if (area == SideTabBarArea::Left)
+	{
+        d->Splitter->addWidget(d->DockArea);
+        d->Splitter->addWidget(emptyWidget);
+	}
+	else
+	{
+        d->Splitter->addWidget(emptyWidget);
+        d->Splitter->addWidget(d->DockArea);
+	}
+
+	// Allows an equal distribution between the empty widget and the splitter
+	const auto frameGeometry = d->DockManager->frameGeometry();
+	const auto leftSize = area == SideTabBarArea::Left ? frameGeometry.width() / 3 : frameGeometry.width();
+	const auto rightSize = area == SideTabBarArea::Left ? frameGeometry.width() : frameGeometry.width() / 3;
+	d->Splitter->setSizes(QList<int>({ leftSize, rightSize }));
+	l->setContentsMargins(QMargins());
+	l->setSpacing(0);
+	l->addWidget(d->Splitter);
+	setLayout(l);
+
+	updateMask();
+	updateSize();
+
+	DockManager->registerOverlayWidget(this);
+
+	d->DockArea->installEventFilter(this);
+	parent->installEventFilter(this);
+}
+
+//============================================================================
+void COverlayDockContainer::updateMask()
+{
+	const auto rect = d->DockArea->frameGeometry();
+	const auto topLeft = rect.topLeft();
+	const auto handleSize = d->Splitter->handleWidth();
+	const auto offset = d->Area == SideTabBarArea::Left ? 0 : handleSize;
+    setMask(QRect(QPoint(topLeft.x() - offset, topLeft.y()), QSize(rect.size().width() + handleSize, rect.size().height())));
+}
+
+//============================================================================
+void COverlayDockContainer::updateSize()
+{
+	const auto dockContainerParent = parentContainer();
+	const auto rootSplitter = dockContainerParent->rootSplitter();
+	const auto rect = rootSplitter->frameGeometry();
+	move(rect.topLeft());
+    resize(rect.width(), rect.height());
+}
+
+//============================================================================
+COverlayDockContainer::COverlayDockContainer(CDockWidget* DockWidget, SideTabBarArea area) : 
+	COverlayDockContainer(DockWidget->dockManager(), area, DockWidget->dockContainer() != nullptr ? DockWidget->dockContainer() : DockWidget->dockManager())
+{
+	addDockWidget(DockWidget);
+}
+
+//============================================================================
+COverlayDockContainer::~COverlayDockContainer()
+{
+	ADS_PRINT("~COverlayDockContainer");
+
+	// Remove event filter in case there are any queued messages
+    parent()->removeEventFilter(this);
+
+	if (d->DockManager)
+	{
+		d->DockManager->removeOverlayWidget(this);
+	}
+
+	delete d;
+}
+
+//============================================================================
+CSideTabBar* COverlayDockContainer::sideTabBar() const
+{
+	return parentContainer()->sideTabBar(d->Area);
+}
+
+//============================================================================
+CDockWidget* COverlayDockContainer::dockWidget() const
+{
+	return d->DockWidget;
+}
+
+//============================================================================
+void COverlayDockContainer::addDockWidget(CDockWidget* DockWidget)
+{
+	if (d->DockWidget)
+	{
+		// Remove the old dock widget at this area
+        d->DockArea->removeDockWidget(d->DockWidget);
+	}
+
+	d->DockWidget = DockWidget;
+    CDockAreaWidget* OldDockArea = DockWidget->dockAreaWidget();
+    if (OldDockArea)
+    {
+        OldDockArea->removeDockWidget(DockWidget);
+    }
+	d->DockArea->addDockWidget(DockWidget);
+
+	updateSize();
+	updateMask();
+}
+
+
+//============================================================================
+SideTabBarArea COverlayDockContainer::sideTabBarArea() const
+{
+	return d->Area;
+}
+
+//============================================================================
+CDockAreaWidget* COverlayDockContainer::dockAreaWidget() const
+{
+	return d->DockArea;
+}
+
+//============================================================================
+void COverlayDockContainer::moveContentsToParent()
+{
+	const auto position = mapToGlobal(d->Area == Left ? QPoint(1,height() / 2) : QPoint(width() - 1, height() / 2));
+
+	const auto dockAreaWidget = parentContainer()->dockAreaAt(position);
+	if (dockAreaWidget != nullptr && !dockAreaWidget->isCentralWidgetArea())
+	{
+        parentContainer()->addDockWidget(CenterDockWidgetArea, d->DockWidget, dockAreaWidget);
+	}
+	else
+	{
+        parentContainer()->addDockWidget(d->Area == Left ? LeftDockWidgetArea : RightDockWidgetArea, d->DockWidget);
+	}
+	cleanupAndDelete();
+}
+
+//============================================================================
+void COverlayDockContainer::cleanupAndDelete()
+{
+	const auto dockWidget = d->DockWidget;
+	if (dockWidget)
+	{
+        dockWidget->sideTabWidget()->removeFromSideTabBar();
+        dockWidget->sideTabWidget()->setParent(dockWidget);
+        dockWidget->sideTabWidget()->hide();
+	}
+	hide();
+	deleteLater();
+}
+
+void COverlayDockContainer::saveState(QXmlStreamWriter& s)
+{
+    s.writeAttribute("SideTabBarArea", QString::number(sideTabBarArea())); 
+	QStringList Sizes;
+    for (auto Size : d->Splitter->sizes())
+    {
+		Sizes << QString::number(Size);
+    }
+
+    s.writeAttribute("Sizes", Sizes.join(" "));
+}
+
+bool COverlayDockContainer::restoreState(CDockingStateReader& s, bool Testing)
+{
+	auto sSizes = s.attributes().value("Sizes").trimmed().toString();
+	ADS_PRINT("Sizes: " << sSizes);
+	QTextStream TextStream(&sSizes);
+	QList<int> Sizes;
+	while (!TextStream.atEnd())
+	{
+		int value;
+		TextStream >> value;
+		Sizes.append(value);
+	}
+
+	if (Sizes.count() != d->Splitter->count())
+	{
+		return false;
+	}
+
+	if (!Testing)
+	{
+		d->Splitter->setSizes(Sizes);
+	}
+
+	return true;
+}
+
+//============================================================================
+bool COverlayDockContainer::eventFilter(QObject* watched, QEvent* event)
+{
+	if (event->type() == QEvent::Resize)
+	{
+		updateSize();
+		updateMask();
+	}
+	return QWidget::eventFilter(watched, event);
+}
+
+//============================================================================
+void COverlayDockContainer::mousePressEvent(QMouseEvent* event)
+{
+    QWidget::mousePressEvent(event);
+}
+
+//============================================================================
+void COverlayDockContainer::resizeEvent(QResizeEvent* event)
+{
+	updateMask();
+    QWidget::resizeEvent(event);
+}
+}
+

src/OverlayDockContainer.h

@@ -0,0 +1,129 @@
+#ifndef OverlayDockContainerH
+#define OverlayDockContainerH
+/*******************************************************************************
+** Qt Advanced Docking System
+** Copyright (C) 2017 Uwe Kindler
+**
+** This library is free software; you can redistribute it and/or
+** modify it under the terms of the GNU Lesser General Public
+** License as published by the Free Software Foundation; either
+** version 2.1 of the License, or (at your option) any later version.
+**
+** This library is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+** Lesser General Public License for more details.
+**
+** You should have received a copy of the GNU Lesser General Public
+** License along with this library; If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+
+//============================================================================
+/// \file   DockWidgetTab.h
+/// \author Syarif Fakhri
+/// \date   05.09.2022
+/// \brief  Declaration of COverlayDockContainer class
+//============================================================================
+
+//============================================================================
+//                                   INCLUDES
+//============================================================================
+#include "ads_globals.h"
+
+#include <QFrame>
+
+class QXmlStreamWriter;
+
+namespace ads
+{
+struct OverlayDockContainerPrivate;
+class CDockManager;
+class CDockWidget;
+class CDockContainerWidget;
+class CSideTabBar;
+class CDockAreaWidget;
+class CDockingStateReader;
+
+class ADS_EXPORT COverlayDockContainer : public QFrame
+{
+    Q_OBJECT
+private:
+    OverlayDockContainerPrivate* d; ///< private data (pimpl)
+    friend struct OverlayDockContainerPrivate;
+
+	CDockContainerWidget* parentContainer() const;
+
+protected:
+	bool eventFilter(QObject* watched, QEvent* event) override;
+	void mousePressEvent(QMouseEvent* event) override;
+	void resizeEvent(QResizeEvent* event) override;
+    void updateMask();
+	void updateSize();
+
+public:
+	/**
+	 * Create overlay widget with a dock manager
+	 */
+    COverlayDockContainer(CDockManager* DockManager, SideTabBarArea area, CDockContainerWidget* parent);
+
+    /**
+	 * Create overlay widget with the given dock widget
+	 */
+	COverlayDockContainer(CDockWidget* DockWidget, SideTabBarArea area);
+
+	/**
+	 * Virtual Destructor
+	 */
+	virtual ~COverlayDockContainer();
+
+	/**
+	 * Get's the side tab bar
+	 */
+	CSideTabBar* sideTabBar() const;
+
+	/**
+	 * Get's the dock widget in this dock container
+	 */
+	CDockWidget* dockWidget() const;
+
+	/**
+	 * Adds a dock widget and removes the previous dock widget
+	 */
+	void addDockWidget(CDockWidget* DockWidget);
+
+	/**
+	 * Returns the side tab bar area of this overlay dock container
+	 */
+	SideTabBarArea sideTabBarArea() const;
+
+	/**
+	 * Returns the dock area widget of this overlay dock container
+	 */
+	CDockAreaWidget* dockAreaWidget() const;
+
+	/**
+	 * Moves the contents to the parent container widget
+	 * Used before removing this overlay dock container 
+	 */
+    void moveContentsToParent();
+
+	/**
+	 * Cleanups up the side tab widget and then deletes itself
+	 */
+	void cleanupAndDelete();
+
+	/*
+	 * Saves the state and size
+	 */
+	void saveState(QXmlStreamWriter& Stream);
+
+	/*
+	 * Restores the size of the splitter
+	 */
+	bool restoreState(CDockingStateReader& Stream, bool Testing);
+};
+}
+
+
+#endif

src/SideTabBar.cpp

@@ -0,0 +1,101 @@
+/*******************************************************************************
+** Qt Advanced Docking System
+** Copyright (C) 2017 Uwe Kindler
+**
+** This library is free software; you can redistribute it and/or
+** modify it under the terms of the GNU Lesser General Public
+** License as published by the Free Software Foundation; either
+** version 2.1 of the License, or (at your option) any later version.
+**
+** This library is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+** Lesser General Public License for more details.
+**
+** You should have received a copy of the GNU Lesser General Public
+** License along with this library; If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+
+//============================================================================
+/// \file   DockWidgetTab.h
+/// \author Syarif Fakhri
+/// \date   05.09.2022
+/// \brief  Implementation of CSideTabBar class
+//============================================================================
+
+
+
+//============================================================================
+//                                   INCLUDES
+//============================================================================
+#include "SideTabBar.h"
+#include "DockContainerWidget.h"
+#include "DockWidgetSideTab.h"
+#include "DockWidgetTab.h"
+
+#include <QBoxLayout>
+
+namespace ads
+{
+/**
+ * Private data class of CSideTabBar class (pimpl)
+ */
+struct SideTabBarPrivate
+{
+	/**
+	 * Private data constructor
+	 */
+	SideTabBarPrivate(CSideTabBar* _public);
+
+    CSideTabBar* _this;
+    CDockContainerWidget* ContainerWidget;
+    QBoxLayout* TabsLayout;
+}; // struct SideTabBarPrivate
+
+//============================================================================
+SideTabBarPrivate::SideTabBarPrivate(CSideTabBar* _public) :
+    _this(_public)
+{
+}
+
+
+//============================================================================
+CSideTabBar::CSideTabBar(CDockContainerWidget* parent) :
+    QWidget(parent),
+    d(new SideTabBarPrivate(this))
+{
+    d->ContainerWidget = parent;
+
+    d->TabsLayout = new QBoxLayout(QBoxLayout::TopToBottom);
+    d->TabsLayout->setContentsMargins(0, 0, 0, 0);
+    d->TabsLayout->setSpacing(0);
+    d->TabsLayout->addStretch(1);
+    setLayout(d->TabsLayout);
+
+    setFocusPolicy(Qt::NoFocus);
+}
+
+
+//============================================================================
+CSideTabBar::~CSideTabBar() 
+{
+	delete d;
+}
+
+
+//============================================================================
+void CSideTabBar::insertSideTab(int Index, CDockWidgetSideTab* SideTab)
+{
+    d->TabsLayout->insertWidget(Index, SideTab);
+    SideTab->setSideTabBar(this);
+}
+
+
+//============================================================================
+void CSideTabBar::removeSideTab(CDockWidgetSideTab* SideTab)
+{
+    const auto index = d->TabsLayout->indexOf(SideTab);
+    d->TabsLayout->removeWidget(SideTab);
+}
+}

src/SideTabBar.h

@@ -0,0 +1,81 @@
+#ifndef SideTabBarH
+#define SideTabBarH
+/*******************************************************************************
+** Qt Advanced Docking System
+** Copyright (C) 2017 Uwe Kindler
+**
+** This library is free software; you can redistribute it and/or
+** modify it under the terms of the GNU Lesser General Public
+** License as published by the Free Software Foundation; either
+** version 2.1 of the License, or (at your option) any later version.
+**
+** This library is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+** Lesser General Public License for more details.
+**
+** You should have received a copy of the GNU Lesser General Public
+** License along with this library; If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+
+//============================================================================
+/// \file   DockWidgetTab.h
+/// \author Syarif Fakhri
+/// \date   05.09.2022
+/// \brief  Declaration of CSideTabBar class
+//============================================================================
+
+//============================================================================
+//                                   INCLUDES
+//============================================================================
+#include <QWidget>
+#include "ads_globals.h"
+
+namespace ads
+{
+struct SideTabBarPrivate;
+class CDockContainerWidget;
+class CDockWidgetSideTab;
+class CDockWidgetTab;
+
+/**
+ * Side tab widget that is shown at the edges of a dock container.
+ */
+class ADS_EXPORT CSideTabBar : public QWidget
+{
+    Q_OBJECT
+private:
+    SideTabBarPrivate* d; ///< private data (pimpl)
+	friend struct SideTabBarPrivate;
+	friend class DockWidgetSideTab;
+
+public:
+    using Super = QWidget;
+
+	/**
+	 * Default Constructor
+	 */
+    CSideTabBar(CDockContainerWidget* parent);
+
+	/**
+	 * Virtual Destructor
+	 */
+	virtual ~CSideTabBar();
+
+	/**
+	 * Inserts the given dock widget tab at the given position.
+	 */
+	void insertSideTab(int Index, CDockWidgetSideTab* SideTab);
+
+	/**
+	 * Removes the given DockWidgetSideTab from the tabbar
+	 */
+	void removeSideTab(CDockWidgetSideTab* SideTab);
+
+	Q_SIGNALS:
+		void sideTabAutoHideToggleRequested();
+};
+}
+
+#endif

src/ads_globals.h

@@ -91,7 +91,8 @@ enum TitleBarButton
 {
 	TitleBarButtonTabsMenu,
 	TitleBarButtonUndock,
-	TitleBarButtonClose
+	TitleBarButtonClose,
+	TitleBarButtonAutoHide
 };
 
 /**
@@ -105,12 +106,24 @@ enum eDragState
 	DraggingFloatingWidget//!< DraggingFloatingWidget
 };
 
+/**
+ * Dock widget side tab bar locations
+ */
+enum SideTabBarArea
+{
+	None,
+    Left,
+    Right,
+	Bottom
+};
+
 /**
  * The different icons used in the UI
  */
 enum eIcon
 {
 	TabCloseIcon,      //!< TabCloseIcon
+	AutoHideIcon,      //!< AutoHideIcon
 	DockAreaMenuIcon,  //!< DockAreaMenuIcon
 	DockAreaUndockIcon,//!< DockAreaUndockIcon
 	DockAreaCloseIcon, //!< DockAreaCloseIcon

src/stylesheets/focus_highlighting.css

@@ -2,7 +2,7 @@
  * Default style sheet on Windows Platforms with focus highlighting flag enabled
  */
 ads--CDockContainerWidget {
-	background: palette(dark);
+	background: palette(window);
 }
 ads--CDockContainerWidget > QSplitter{
         padding: 1 0 1 0;
@@ -22,6 +22,14 @@ ads--CDockWidgetTab {
 	qproperty-iconSize: 16px 16px;/* this is optional in case you would like to change icon size*/
 }
 
+ads--CDockWidgetSideTab {
+	background: palette(window);
+	border-color: palette(light);
+	border-style: solid;
+	border-width: 1px 1px 1px 1px;
+	padding: 0 0px;
+}
+
 ads--CDockWidgetTab[activeTab="true"] {
 	background: qlineargradient(spread : pad, x1 : 0, y1 : 0, x2 : 0, y2 : 0.5, stop : 0
 		palette(window), stop:1 palette(light));
@@ -100,6 +108,10 @@ ads--CDockWidgetTab[focused="true"] {
 	border-color: palette(highlight);
 }
 
+ads--CDockWidgetSideTab[focused="true"] {
+	border-color: palette(highlight);
+}
+
 ads--CDockWidgetTab[focused="true"]>#tabCloseButton {
 	qproperty-icon: url(:/ads/images/close-button-focused.svg)
 }
@@ -126,4 +138,4 @@ ads--CDockAreaWidget[focused="true"] ads--CDockAreaTitleBar {
 	background: transparent;
 	border-bottom: 2px solid palette(highlight);
 	padding-bottom: 0px;
-}
+}