I don't know how I came to use `key_exists()` as all Google comes up with is `array_key_exists()`.  It's most definitely **not** down to me being a crusty old PHP programmer and that is how I've always done it, regardless of what my avatar suggests ;-)

I see your point about this being off by default.

I've also noticed with this in place, that unlike web-pages, the navigation doesn't highlight the current page for Apps.  That is, the `class="current` isn't added to the `<li>`.  This is because, by default, `$page->id` is not set for apps.  Simply adding:-
```php
$page->id = 'blog'; // or whatever the app is called
```
or to allow for renaming Apps (if that is at all possible) or as a simple copy/paste boilerplate:-
   ```php
$handler_array = explode('/',$handler);
$page->id = $handler_array[1];
```
to a handler (or many handlers in the case of e.g. Blog - `by.php`, `headlines.php`, `index.php`, `post.php` and `tags.php`) will cause the navigation app to highlight the current page.