The shader to RGB node disappeared from the menu in the main project scene.
I can create a new scene and it does appear there.
If I place the node in that new scene, I can copy and paste it into the main scene. Despite this, the node still does not appear in the menu.
Thank you.
EDIT
Although this question gives also the answer to mine question, one cannot be substituted for the other. The answer is related, yes, but the question is different. If a user sees that his node has disappeared from his menu, he can find my question with the corresponding solution, he would never find the other question, since for that he would have to know that it is a problem related to the rendering engine.