I want to be able to fold on the line before the opening brace "{" . But I haven't been able to come up with a foldingStartMarker that works for it.
My guess is that the foldingMarkers are stuck on single line mode.
Yeah, all matches in TextMate are limited to a single line. Any more and you'd have to re-evaluate too much every single keypress, just too much to process. The only solution I've heard allan talk about is something like a two stage regex, it would match one regex and then only watch for the second regex on the following line. But I wouldn't expect anything like that for a long while I bet.
As for your issue, the only way I can see it working is just wrapping on the {}, but it does make it two lines rather than the one.