Constraint Validation Bubbles Gone In Opera 16 on OS X

Question

In Opera 16, the constraint validation bubbles no longer display. This can be recreated on the simplest of examples, compare what happens here in Opera and Chrome:

<form>
    <input required>
    <button>Go</button>
</form>

http://jsfiddle.net/tj_vantoll/7qPRm/

Since Opera is now Blink based, it should inherit Chrome's exact implementation, but this issue is not present in Chrome. Anybody know what's up?

Edit: This appears to be OS X only. Things seem fine on Windows.

Answer 1

This was a bug in Opera 16 that was fixed in Opera 17.