Mail opt checkbox becomes uneditable when user selects another checkbox and unselects

Checkbox field becomes uneditable even after setcardinality(optional) is set

We are trying to make a checkbox field editable based on other field value. We are using setcardinality(optional) to make the field editable after disabling the field.

so the check-box remains uneditable even after setCardinality(OPTIONAL) is being set.

Im using getFieldDef(MAIL_OPT_IN_FIELD).setValue(false); method to set the value of checkbox false and after this when need to change to true and editable i'm using getFieldDef(MAIL_OPT_IN_FIELD).setCardinality(ICardinality.OPTIONAL);

Other normal string value fields are getting editable but boolean value field is not getting editable.