I'm not sure we need to have destroyOnClose in the popup instance. The scope includes a reference to the options so we can probably use this.scope.options.destroyOnClose in the close function.

```
Popup.prototype.close = function() {
  this.element.hide();

  var destroyOnClose = this.scope.options.destroyOnClose;
  if (destroyOnClose !== false) {
    this.destroy();
  }
};
```