Fixed issue #164 - Single DockArea cannot be split

Author: githubuser0xFFFF

src/DockAreaTitleBar.cpp

@@ -589,7 +589,7 @@ void CDockAreaTitleBar::mouseMoveEvent(QMouseEvent* ev)
         return;
     }
 
-	// If this is the last dock area in a dock container it does not make
+	// If this is the last dock area in a floating dock container it does not make
 	// sense to move it to a new floating widget and leave this one
 	// empty
 	if (d->DockArea->dockContainer()->isFloating()
@@ -612,7 +612,7 @@ void CDockAreaTitleBar::mouseMoveEvent(QMouseEvent* ev)
 	int DragDistance = (d->DragStartMousePos - ev->pos()).manhattanLength();
 	if (DragDistance >= CDockManager::startDragDistance())
 	{
-        ADS_PRINT("CTabsScrollArea::startFloating");
+        ADS_PRINT("CDockAreaTitlBar::startFloating");
 		d->startFloating(d->DragStartMousePos);
 		auto Overlay = d->DockArea->dockManager()->containerOverlay();
 		Overlay->setAllowedAreas(OuterDockAreas);

src/FloatingDragPreview.cpp

@@ -33,7 +33,6 @@ struct FloatingDragPreviewPrivate
 	CFloatingDragPreview *_this;
 	QWidget* Content;
 	CDockAreaWidget* ContentSourceArea = nullptr;
-	CDockContainerWidget* ContenSourceContainer = nullptr;
 	QPoint DragStartMousePosition;
 	CDockManager* DockManager;
 	CDockContainerWidget *DropContainer = nullptr;
@@ -123,22 +122,8 @@ void FloatingDragPreviewPrivate::updateDropOverlays(const QPoint &GlobalPos)
 	int VisibleDockAreas = TopContainer->visibleDockAreaCount();
 	ContainerOverlay->setAllowedAreas(
 	    VisibleDockAreas > 1 ? OuterDockAreas : AllDockAreas);
-
-	DockWidgetArea ContainerArea = InvalidDockWidgetArea;
-	// If there is only one single visible dock area in a container, then
-	// it does not make sense to show a dock overlay because the dock area
-	// would be removed and inserted at the same position
-	if (VisibleDockAreas <= 1)
-	{
-		ContainerOverlay->hideOverlay();
-	}
-	else
-	{
-		ContainerArea = ContainerOverlay->showOverlay(TopContainer);
-	}
-	ContainerOverlay->enableDropPreview(ContainerArea != InvalidDockWidgetArea);
 	auto DockArea = TopContainer->dockAreaAt(GlobalPos);
-	if (DockArea && DockArea->isVisible() && VisibleDockAreas > 0 && DockArea != ContentSourceArea)
+	if (DockArea && DockArea->isVisible() && VisibleDockAreas >= 0 && DockArea != ContentSourceArea)
 	{
 		DockAreaOverlay->enableDropPreview(true);
 		DockAreaOverlay->setAllowedAreas(
@@ -149,8 +134,7 @@ void FloatingDragPreviewPrivate::updateDropOverlays(const QPoint &GlobalPos)
 		// the mouse is in the title bar. If the ContainerArea is valid
 		// then we ignore the dock area of the dockAreaOverlay() and disable
 		// the drop preview
-		if ((Area == CenterDockWidgetArea)
-		    && (ContainerArea != InvalidDockWidgetArea))
+		if ((Area == CenterDockWidgetArea) && (ContainerDropArea != InvalidDockWidgetArea))
 		{
 			DockAreaOverlay->enableDropPreview(false);
 			ContainerOverlay->enableDropPreview(true);
@@ -159,10 +143,24 @@ void FloatingDragPreviewPrivate::updateDropOverlays(const QPoint &GlobalPos)
 		{
 			ContainerOverlay->enableDropPreview(InvalidDockWidgetArea == Area);
 		}
+		ContainerOverlay->showOverlay(TopContainer);
 	}
 	else
 	{
 		DockAreaOverlay->hideOverlay();
+		// If there is only one single visible dock area in a container, then
+		// it does not make sense to show a dock overlay because the dock area
+		// would be removed and inserted at the same position
+		if (VisibleDockAreas <= 1)
+		{
+			ContainerOverlay->hideOverlay();
+		}
+		else
+		{
+			ContainerOverlay->showOverlay(TopContainer);
+		}
+
+
 		if (DockArea == ContentSourceArea && InvalidDockWidgetArea == ContainerDropArea)
 		{
 			DropContainer = nullptr;
@@ -270,7 +268,6 @@ CFloatingDragPreview::CFloatingDragPreview(CDockWidget* Content)
 	if (Content->dockAreaWidget()->openDockWidgetsCount() == 1)
 	{
 		d->ContentSourceArea = Content->dockAreaWidget();
-		d->ContenSourceContainer = Content->dockContainer();
 	}
 	setWindowTitle(Content->windowTitle());
 }
@@ -282,7 +279,6 @@ CFloatingDragPreview::CFloatingDragPreview(CDockAreaWidget* Content)
 {
 	d->DockManager = Content->dockManager();
 	d->ContentSourceArea = Content;
-	d->ContenSourceContainer = Content->dockContainer();
 	setWindowTitle(Content->currentDockWidget()->windowTitle());
 }