[OH3] Code completion in build in rule editor?

I’m into migrating my existing 2.5 setup to OH3.
Fantastic job from the whole team, I really appreciate your work.
Especially the new GUI is absolutely amazing.

The only thing I couldn’t figure out so far:
How can I get (enable) code completion in the build in code editor as demonstrated by Yannick in the " openHAB Virtual MeetUp 2020" video? Tried it out for both the old DSL Rules as well as for JavaScript,
but no completion.