Ctrl+Space should provide auto-completion for keywords and section headings in Lab after you have typed a couple of characters.
Auto completion is a bit lazy. I often first need to execute the settings. And even then it seems to take a while until lab knows what is available. I usually proceed in that order until it is working:
- execute settings cell
- run activity
- rebuilt environment
At some point it starts working consistently. If anything from the above helps, I don’t know. Maybe it only needs time