radios - checkboxes : all selected when validation fails

Say i have a form with checkboxes or radio buttons in it, with no default values attached to them (meaning the blank form shows no pre-selected checkbox or radio).

I submit the form without checking any checkbox / radio, and say for any reason (for example, i left required fields empty...) the validation fails.

BUG : When the form is displayed back, all radios or checkboxes are checked
(of course for radio buttons, only one is selected - the last one-, but in the html they all are tagged 'checked="checked"')

The error probably lies in
function theme_radio - line 542 and
function theme_checkbox - line 726 :
the comparison between the form returned value (0 in my case) and the checkbox / radio value should use === instead of == :
(0 == 'any chain') is true.

The proposed patch corrects this, but I'm not at all familiar with the internal mechanics of the forms system, so I shouldn't know if this breaks anything alse...