firing FORM_PROCESS_SUBMIT_EVENT, but form is not submitted

[Ray Nicholus]

I've confirmed that the following line of code in my js is executed:

$(spec.formId).fire(Tapestry.FORM_PROCESS_SUBMIT_EVENT);

I've also confirmed that $(spec.formId) is the correct form element, and the
form element exists.  However, this line does NOT submit my form.  Any idea
what might cause this?