I spent a few hours on this last night but couldn't solve it, I can't figure out why the temp file isn't being created. But I did unravel your nest to make it easier to follow the flow - https://github.com/christophhart/HISE/pull/651
yes that's a known issue. Unfortunately solving it means that the code tokenizer would have to scan the entire file to grab the correct colours which comes with a huge performance hit on large files. It's obviously possible to solve that, but not super trivial.