Creates a new tabbed group and adds it to the current group.
The created group.
The default layout type is determined by the LayoutGroup.DefaultLayoutType property. By default, it is set to LayoutType.Vertical, so the new group is positioned at the bottom of the current group. If this property is set to LayoutType.Horizontal, the new group is positioned at the current group's right edge.
To add tabs to the new tabbed group, use the TabbedGroup.AddTabPage method.