Losing highlighting after line break

[BPJ]

I solved the problem I had yesterday — I had missed that the `matchgroup=Group` for a region must come before the `start=...` and `end=...`.

Now I have run into another problem: I sometimes lose highlighting of contained items and the end of a region after a linebreak inside a region. Since I can't remember having seen this before I'm probably doing something wrong in my syntax script. I have searched for /line in syntax.vim but not found anything relevant. (Not the first time my main problem with :help is that I can't find what I'm looking for!)