It's essential for me to find a tool that will reverse engineer sequence diagrams by integrating with the debugger. I suppose using the profiler could work also but less desirable. It's a key requirement that the tool in question will record all threads of execution since the app, TickZoom, is heavily parallelized.

We just evaluated a most awesome tool from Sparx called Enterprise Architect which integrates with the debugger. It allows you to set a break point, start recording method traces from that break point.

It's a lovely design and GUI. Hope it works for you but it only records a single thread of execution so that makes it unusable for us. I will put in a feature request to Sparx. But hope to find a similar tool that already does this since that's the only feature we need--not all the other amazing features that Sparx Enterprise Architect appears to do rather well.