Window | New Horizontal Tab Group

Splits the current system's main application window into sections and displays tab groups horizontally on top of each other. This can also be accomplished by dragging a tab into the window area and releasing.

Tab groups can only be split one direction; vertically or horizontally. Once a group is created, the other option is replaced with the Move to Next Tab Group option.

Note: This option is only available when using a Tabbed interface.