function buildBillableCheckbox(projectParam, taskParam) {
        var billableCheckbox = AJS.$("#worktime-dialog #billable");
        var isChecked = false;
        if (projectParam != null && taskParam != null) {
            if ((taskParam.accountableType != null && taskParam.accountableType != "none")
                || (taskParam.accountableType == null && projectParam.billable == "true") ) {
                isChecked = true;
            }
            billableCheckbox.prop('checked', isChecked);
            if (!isChecked) {
                AJS.$('#worktime-dialog #reasonsNotAccountable').parent().show();
            } else {
                AJS.$('#worktime-dialog #reasonsNotAccountable').parent().hide();
            }
        }
        billableChange(); //enable billable change trigger
    }