Function updateSelection

static/editor.md/lib/codemirror/lib/codemirror.js:2197–2199

(cm)

  // SELECTION DRAWING

  function updateSelection(cm) {
    cm.display.input.showSelection(cm.display.input.prepareSelection());
  }

  function prepareSelection(cm, primary) {
    var doc = cm.doc, result = {};