This issue was originally filed by matsond...@gmail.com

What steps will reproduce the problem?

1. Run simple program below.
   import 'dart:html';

void main() {
  KeyboardEventStream.onKeyDown(document.body).listen(_keydownHandler);
}

void _keydownHandler(KeyEvent e) {}

1. Press control + shift and release.
2. On releasing control exception is thrown

What is the expected output? What do you see instead?
Expected is control keys is returned in KeyEvent, instead exception is thrown.

What version of the product are you using? On what operating system?
Windows 7 x64.
Chromium 28.0.1500.0 (Developer Build 198577)
OS Windows
Blink 537.36 (Source@1262)
JavaScript V8 3.18.5.2
DartVM 0.5.13.1_r23552

Please provide any additional information below.

This happens on many other combinations of keys as well.
If you look in the KeyEvent the field $dom_keyIdentifier="<Exception thrown>"