When having a button-element with type=submit contain another element (such as a label), clicking the containing element will not trigger form-submission.
Clicking directly on the button (instead of the child element) will trigger submission as expected.
The example urls shows the minimum code that provokes this error. The form-submission prints the current time in a span after the form, to show that something has happened.
The button does receive click-events properly, so adding 'onclick=this.form.submit()' to the button will make the form submit, but that should not be necessary, and also avoids triggering the submit-event for the form.
See also: bug 16868, bug 89041.
Bug 15696, not 16868.
Created attachment 169684 [details]
same test as attachment