add: else { properties.AppendElement(ltnGetAtom("unchecked")); } 
context:     getCellProperties: function (row, col, properties)    {        if (col.id == "col-calendar-Checkbox") {            var cal = getCalendars()[row];            if (getCompositeCalendar().getCalendar(cal.uri)) {                properties.AppendElement(ltnGetAtom("checked"));            }        }    },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/8395/1a64476844ed4fd0c25a94c8eedeb6014803348d/calendar-management.js/clean/calendar/lightning/content/calendar-management.js