Public attributes and slots
labelopendisabledaria-labelhiddenclassdir
label supplies fallback trigger text (Dropdown). open="false" closes the panel;
other values open it, preserving source visibility semantics (default true). disabled and
hidden use presence. aria-label names the fallback trigger separately.
class and dir are supported. The base slot replaces the trigger; the
default slot supplies panel content.
Use native click, Enter or Space to toggle, ArrowDown to open and focus, Escape to close and restore focus. Tab and outside activation dismiss without a trap. Menu leaf activation dismisses the complete popup chain. Exercise real hover, press, keyboard focus and expansion. Each example includes five horizontal-rule siblings: an open panel paints over them, and closing it reveals the same rules underneath.
Arbitrary content
Custom content
Unavailable
Hidden content
Custom panel