[Designer] How to make a standalone widget from some subpart of a QMainWindow ?

[aCOSwt]

• I have designed a main window form class => in terms of objects, I get something like :
  @whatever [QMainWindow]
  • centralwidget [QWidget]
    + one_tab [QTabWidget]
    + first_tab [QWidget]
    ... All the objects of the first_tab@
    I now realize that it would be convenient at run time to be able to add new tabs identical to the first one.
    => I would like to design an "autonomous" widget including all the objects of the first tab in order to be able to code something like :
    @one_tab->addTab(autonomous_w, QString());@

How can I easily achieve this (without of course restarting the design from scratch) ?

[aCOSwt]

OK it seems I sorted this out when discovering how to select a group of objects from the object inspector window then copy + paste in another form.