Public attributes and slots
directionjustifykeyboardaria-labelaria-labelledbydirhiddenclass
direction="row|column" defaults to row; submenu panels default to column. justify="start|end" defaults to start; keyboard="native|menu" defaults to native. aria-label, aria-labelledby, dir, hidden and class are supported. The default slot accepts links, buttons, menu items and content. Nested menus belong in an item's submenu slot. Item href creates a leaf link; submenu owners remain buttons.
Exercise real hover, press and Tab focus. Menu mode adds orientation arrows, Home/End, typeahead and Escape. Only one sibling submenu opens. Roots remain visible.