Create an anchor that selects every web page

how would i properly create an anchor that selects the top level element. the goal is to create a window on every single tab that is positioned in the bottom right. export const getOverlayAnchor: PlasmoGetOverlayAnchor = () => { return document.querySelector('html'); }; this solution seems to have some issues with some pages when the html element is modified, causing the anchor to be lost. Is there a more reliable way to just select any web page in such a way that a absolutely positioned container can be rendered?