The wikitext insertion warning now works, and is visible regardless of the position of the user on the page.
However, its color scheme is the same as other regular, confirmation-type notifications like "you've added this page to your watchlist".
Wikitext insertion is an actual problem, rather than "just" a confirmation or feedback notification. We need it to be more visible, possibly by using a different color scheme. Maybe not a big red blinking bubble, but something more noticeable than a white bubble with a light blue border.