Ahh, to be fair that’s a ‘MakeCode TypeScript is not like javascript’ part - we’re a subset of TypeScript, which is a superset of JavaScript (see https://makecode.com/language).
and ahh, I had misunderstood it – I was assuming it was just a wrapper around a delayed setting of the flag, have to read it. Not sure that’s going to be something that’s supported right away. You can try something like: Making my own block that has a body and is not a top block that wraps the blocks in the overlap?