List Style (2 column)
[submenu-items parent_id="27" cols="2"]
Button Style (3 column, open in new tab)
[submenu-items parent_id="27" cols="3" type="button" open="new"]
Button Style (2 column)
[submenu-items parent_id="27" cols="2" type="button"]
Button Style (1 column)
[submenu-items parent_id="27" type="button"]