Hi,
you can achieve this by javascript,
example could be found in detail category form (detail_isscat, pcat, chgcat),
where when you click Include SS, ss_sym attribute displays.
But this will not work with complex headers like calendar inputs or lookups so you need to make your own function.
Algorithm will look like:
I.1. get input element;
I.2. get input elements parent (td element);
I.3. hide it/show it;
II.1. get label for input element;
II.2. get labels parent (td or th element);
II.3. hide it/show it;
III.1. mark/unmark field as required.
Regards,
cdtj