This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
In the lifecycle explanation it says "attachedCallback, which is called after a custom element is inserted into a document with a default view; detachedCallback" but according to the latest custom element spec those have been renamed into "enteredView" and "leftView", see http://w3c.github.io/webcomponents/spec/custom/index.html#types-of-callbacks for details.
The spec has not been updated with the outcome of https://www.w3.org/Bugs/Public/show_bug.cgi?id=24314, the bug that changed the names from enteredViewCallback and leftViewCallback to attachedCallback and detachedCallback.
Moved to https://github.com/w3c/webcomponents/issues/227