This event is emitted when a root <dropdown-menu> is about to be opened. It does not
get emitted when a sub-menu opens.
When a menu is to be opened, a non-bubbling version of this event is emitted on the
<dropdown-menu>. If that event isn't cancelled, (that is, if preventDefault() was
not called) a bubbling version of this event is emitted on the element which originally triggered the opening of the
menu. If that event also isn't cancelled, then the default behaviour of the original "click" or "contextmenu"
event will be prevented, and the menu will open. Otherwise, the default behaviour of the original event will not be
prevented and the menu will not open.
The event type used in
element.addEventListener("dropdownOpen", ...)This is a DOM event using the
CustomEventtype with the event name"dropdownOpen". TheDropdownOpenEventDetailswill be on the.detailsproperty of this object.This event is emitted when a root
<dropdown-menu>is about to be opened. It does not get emitted when a sub-menu opens.When a menu is to be opened, a non-bubbling version of this event is emitted on the
<dropdown-menu>. If that event isn't cancelled, (that is, ifpreventDefault()was not called) a bubbling version of this event is emitted on the element which originally triggered the opening of the menu. If that event also isn't cancelled, then the default behaviour of the original"click"or"contextmenu"event will be prevented, and the menu will open. Otherwise, the default behaviour of the original event will not be prevented and the menu will not open.Upon opening, a new
<active-dropdown-menu>is created.