AngularJS disables (cannot submit) forms that do not have a specific action set:
<form action="">
when you create a controller. It does not have this issue when creating directive or factories.
You can see this in a plunk here:
http://plnkr.co/edit/gWFRMKGO3FzZtOgs4VmW?p=preview
Form is defined as:
<form action="" method="post">
If you delete the starting on line 6, you will be able to submit the form.
A simple solution is to define the action, but I'd rather not do this, as it is not necessary.
UPDATE
Some details can be found here on trying to get this change in Angular: