Gecko (Firefox Nightly 37.0a1 (2015-01-04)) leaks shadowed elements to document.activeElement
(though not through FocusEvent
)
and it does not implement ShadowRoot.activeElement
.
See Shadow DOM 6.3 Active Element
Expected values are document.activeElement = '#first-shadow-host'
and firstShadowRoot.activeElement = '#second-shadow-host'
.
Note: I peg this bug to be the cause for Gecko dispatching FocusEvent
s if the focus stayed
within the same ShadowRoot and there shouldn't be a change to document.activeElement
. At least
I consider this a bug per Shadow DOM 5.8 Event Dispatch: If the relatedTarget and target are the same for a given node, its the event listeners must not be invoked.
In Firefox the setting dom.webcomponents.enabled
needs to be set to true
to enable ShadowDOM support.