extension/js_fix

TreeElement.prototype.isEventWithinDisclosureTriangle = function(event) {
  var computedLeftPadding = 10;
  if(window.getComputedStyle(this._listItemNode).getPropertyCSSValue) {
    computedLeftPadding = window.getComputedStyle(this._listItemNode).getPropertyCSSValue("padding-left").getFloatValue(CSSPrimitiveValue.CSS_PX);
  }
  var left = this._listItemNode.totalOffsetLeft() + computedLeftPadding;
  return event.pageX >= left && event.pageX <= left + this.arrowToggleWidth && this.hasChildren;
}