t body = [];
  head.push(`<th></th>`);

  for (let i = 0; i < 130; ++i) {
    head.push(`<th>Column ${i}</th>`);

    const tr = [];

    tr.push(`<th>Row ${i}</th>`);
    for (let j = 0; j < 130; ++j) {
      tr.push(`<td><div class="markable-cell">${j}</div></td>`);
    }
    body.push(`<tr>${tr.join("")}</tr>`);
  }

  theadElement.innerHTML = `<tr>${head.join("")}</tr>`;
  tbodyElement.innerHTML = body.join("");

  const selecto = new Selecto({
    container: document.body,
    selectableTargets: [".tab