ConstThe shared portal container is used ONLY in fullscreen, where the tooltip has to be mounted under
the fullscreen element to be visible at all. Outside it, the tooltip stays on MUI's own default
(document.body): the shared container carries a z-index, which makes it a stacking context
that caps everything inside it — and a tooltip's whole point is that it out-stacks the menu or
dialog it is describing.
SimpleTooltip wraps that use the useFullscreenPortal hook to wrap MUI Tooltip and set the Popper container to support fullscreen/portal scenarios. Behaves exactly like Tooltip.