This issue was originally filed by @chrisbu

What steps will reproduce the problem?

1. Write Code such as:
   http://stackoverflow.com/questions/17292762/dart-unhandledexceptioncallback-is-ignored

import 'dart:isolate';

void isolateMain() {
  throw new Exception("ouch");
}

bool handleException(IsolateUnhandledException e) {
  print("EXCEPTION in isolate: " + e.toString());
  return true;
}

void main() {
  SendPort sendPort = spawnFunction(isolateMain, handleException);
  sendPort.call("Hello").then((e) {
    print("Main received " + e);
  });
}

1. handleException function is never called.

What is the expected output? What do you see instead?

Expect handleException to be called.

What version of the product are you using? On what operating system?

Dart VM version: 0.5.20.4_r24275 (Fri Jun 21 05:02:50 2013) on "macos_x64"

Please provide any additional information below.

Taken from SO question:
http://stackoverflow.com/questions/17292762/dart-unhandledexceptioncallback-is-ignored

which was raised in response to SO question:
http://stackoverflow.com/questions/17271178/dart-web-server-prevent-crash/17271530#­17271530