Multi-select and checkbox values are cleared out from "Tab" custom groups when contact is saved

This is because we do not filter on the custom group being inline in Edit.php and hence retrieve all custom groups and reset checkboxes if we dont see it in POST.

Check: http://forum.civicrm.org/index.php/topic,2542.msg10844.html#msg10844

for more details. I think this bug has been there since v1.8, kinda surprised and sad that we did not catch this till now.