lib/assets/scripts/vendor/codemirror/codemirror.js
function startWorker(cm, time) {
    if (cm.view.frontier < cm.display.showingTo)
      cm.view.highlight.set(time, bind(highlightWorker, cm));
  }
function startWorker(cm, time) {
    if (cm.view.frontier < cm.display.showingTo)
      cm.view.highlight.set(time, bind(highlightWorker, cm));
  }
HIGHLIGHT WORKER