code: function updateSelectionCursor(cm) {
      var display = cm.display, pos = cursorCoords(cm, cm.doc.sel.head, "div");
      display.cursor.style.left = pos.left + "px";
      display.cursor.style.top = pos.top + "px";
      display.cursor.style.height = Math.max(0, pos.bottom - pos.top) * cm.options.cursorHeight + "px";
      display.cursor.style.display = "";
  
      if (pos.other) {
        display.otherCursor.style.display = "";
        display.otherCursor.style.left = pos.other.left + "px";
        display.otherCursor.style.top = pos.other.top + "px";
        display.otherCursor.style.height = (pos.other.bottom - pos.other.top) * .85 + "px";
      } else { display.otherCursor.style.display = "none"; }
    }
docs: No selection, plain cursor