Adding separators between commands
A command separator is a horizontal line that you can add to menus to group similar or related commands. You can add separators between commands on any menu, in any window.
To add a separator between commands
From the Tools menu, point to Customize, and then click Menus and Toolbars.
Once the Customize Menus and Toolbars dialog box is open, the menus and toolbars are active and editable.
Place your cursor where you would like to add a separator, and then right-click.
From the right-click menu, click Begin Group.
The separator is added in front of the selected command.