Notebook.setTabDetachable

Sets whether the tab can be detached from notebook to another notebook or widget.

Note that 2 notebooks must share a common group identificator (see [gtk.notebook.Notebook.setGroupName]) to allow automatic tabs interchange between them.

If you want a widget to interact with a notebook through DnD (i.e.: accept dragged tabs from it) it must be set as a drop destination and accept the target “GTK_NOTEBOOK_TAB”. The notebook will fill the selection with a GtkWidget** pointing to the child widget that corresponds to the dropped tab.

Note that you should use [gtk.notebook.Notebook.detachTab] instead of [gtk.container.Container.remove] if you want to remove the tab from the source notebook as part of accepting a drop. Otherwise, the source notebook will think that the dragged tab was removed from underneath the ongoing drag operation, and will initiate a drag cancel animation.

static void
on_drag_data_received (GtkWidget        *widget,
                       GdkDragContext   *context,
                       gint              x,
                       gint              y,
                       GtkSelectionData *data,
                       guint             info,
                       guint             time,
                       gpointer          user_data)
{
  GtkWidget *notebook;
  GtkWidget **child;

  notebook = gtk_drag_get_source_widget (context);
  child = (void*) gtk_selection_data_get_data (data);

  // process_widget (*child);

  gtk_notebook_detach_tab (GTK_NOTEBOOK (notebook), *child);
}

If you want a notebook to accept drags from other widgets, you will have to set your own DnD code to do it.