@JotaMG, it would be great if you just open a new topic, this follow up question has no relation to Plone js/css.
Did someone make another way of designating which Dexterity fields should be included in SearchableText that I'm not aware of?
Actually no, I was wrong.
So collective.dexteritytextindexer would be useful, nevertheless it is not Plone 5 compliant at the moment.
I am pretty sure there are not many changes to do to make it compliant, but still, we need to work on it.
Here is a PR https://github.com/collective/collective.dexteritytextindexer/pull/13, the changes were small.