Valid button for editing textfile does not appear on paste

[scenaristeur]

When I want to edit a file the valid/save button has disappear.

On https://holacratie.solid.community/public/Schema Edit: Well in fact, it has not really disappear, it is here, but it only appear when I change the text. The first attempt was only by copying text. The change is detected when you type text, not when you only paste but I think paste should be detected too