 {
            let selector = document.createElement('a');
            selector.className = 'selector selector-active';
            selector.appendChild(document.createTextNode(elem));
            systems.appendChild(selector);
            if (!(elem in selectors.system)) { selectors.system[elem] = data.some(entry => entry.system == elem && !entry.hide); }
            selector.addEventListener('click', e => toggle(e, elem, selectors.system));

            // Highlighting summary rows and table columns on ho