The "disabled" attribute for a Submit button is currently loosely documented as :
" ... Further, a disabled field ignores any value in the request when the form is submitted."
I would like it to be more explicit, along the lines of:
" ... Further, if bound, the disabled attribute is re-evaluated upon form submission and the "selected" event is only fired should it evaluate to 'false'."
For this stumped us in work today for a good half hour - it was because we weren't @Persist'ing our disabled attribute. Our expression was t:disabled="!myObject" and of course 'myObject' because null / false on form submission. As our submit button was enabled and the form submitted, we saw no reason for the event not to fire.