Such reports should be posted in the Report An Issue section of the forum so that it can be brought to the attention of FileMaker Inc.'s TS personnel.
For what it's worth, I've been making fairly extensive use of the debugger in FileMaker 12 on windows 7 and XP and have not encountered this specific issue.
Thanks for the suggestion - I just posted over there too.
All of our Windows install of Advanced have exhibited this behavior from day one with 12. And now with 12v4 on Mac it has it too - this is not a single machine problem.
No, but as I have commented over in your Issue Report, it might be due to an issue with your file...
OK - I guess either way it's a bug in FMP 12 that didn't exist in previous versions...