As per phab:T348286, popups should be attached to the HTML element returned by OO.ui.getTeleportTarget(). Can the examples on this page be updated to show best practices using this API, instead of the current code that appends the popups to document.body ? I'm not sure if one of the following ways is recommended over the other: convert the teleport target to a jQuery object and append the jQuery object for the popup, or extract the first HTML element from the jQuery object for the popup and append it to the teleport target.