The debugger is, IMO, one of the most useful features of TWS but it seems to be working less and less for me. Lately, it seems like I'm lucky to have the debugger work 10% of the time. Very frustrating.
Most times, I try to start debugging - from a unit test or from a debug log - and it just stops like the transaction has finished, even though I know it's at the start of a very long log. That or the debugger doesn't really start - the windows for locals/call stack/etc show up and the title bar changes to says"running" but there's nothing on the stack and the buttons for step in/out/etc are not there. The only way out of this (that I can find) is to restart TWS.
This seems to happen when there are managed packages present but I'm not 100% sure on that. If there is something I can do to help TWS figure this out, please let me know.