annoying "developer-view styles" button overlaps text

"http://www.w3.org/TR/html5/syntax.html#determining-the-character-encoding <http://www.w3.org/TR/html5/syntax.html#determining-the-character-encoding>"

That annoying floating button prevents me from reading the text.
Either reserve a place for it that does not overlap the text, or add a
hide button allowing to hide it.
It's so obvious, I cannot believe I'm reporting this. It's the most
stupid thing I've ever seen.