Add QMainWindow::GroupedDragging DockOption

If this setting is enabled, the entire group of docked tabs will
be draggable by the title bar of the group and and individual dock
can be dragged by dragging the tab.

When tabs are detached, the docks that are contained are reparented to
a QDockWidgetGroupWindow.

[ChangeLog][QtWidgets][QMainWindow] Added GroupedDragging as a DockOption
which allow users to drag all the tabs together when dragging the
title of a QDockWidget which is tabbed with others.

Change-Id: I5285685b129770498eb3e4fd5f4556e41225a595
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Paul Olav Tvete <paul.tvete@theqtcompany.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/examples/widgets/mainwindows/mainwindow/colorswatch.h b/examples/widgets/mainwindows/mainwindow/colorswatch.h
index 6d02592b22..78f267c320 100644
--- a/examples/widgets/mainwindows/mainwindow/colorswatch.h
+++ b/examples/widgets/mainwindows/mainwindow/colorswatch.h
@@ -70,8 +70,10 @@ class ColorSwatch : public QDockWidget
 
     QAction *windowModifiedAction;
 
+    QMainWindow *mainWindow;
+
 public:
-    explicit ColorSwatch(const QString &colorName, QWidget *parent = 0, Qt::WindowFlags flags = 0);
+    explicit ColorSwatch(const QString &colorName, QMainWindow *parent = 0, Qt::WindowFlags flags = 0);
 
     QMenu *menu;
     void setCustomSizeHint(const QSize &size);