In Rodin 3.8, we implemented [feature-requests:#371]. This change has inconvenienced several users, particularly because the rewriting reasoners (eh/he) only rewrite the selected hypotheses: since the rewritten hypothesis is then hidden, the deselected hypotheses are not rewritten but do not contain the equality either.
There seems to be two options: deselecting the rewritten hypothesis instead of hiding it or rewriting both the selected and deselected sets of hypotheses.
The right option is that of #818.