How to know an dock widget of an main window is out of it or not?

As you know,there are dock widgets in the example 'Dockets Widgets',and when I double-click it or drag it, I can let it be out of the main window.
Now I want to know that when it is in the main window,and when it is out of the main window?

QDockWidget::isFloating()

1.How to let 9 dockwidgets lie in 3 rows,and each row has 3 dockwidgets?
that is, I want to let many dockwidgets line up with any rows and any lines.

2. How to let a dockwidget has a maximum icon on the right-up corner,I find that there is only a closed icon on the corner when it is floating.


3. If dockwidget can not satisfy what I said,could you tell me another method?


Thank you in advance.