Fifty – fifty. The problem for the menu comes from your theme, and the problem for the slider comes from Polylang…
I propose you the following modifications:
In the file header.php of your theme, line 46, replace:
<?php wp_nav_menu(array('menu' => 'Top menu', 'theme_location' => 'Top menu', 'depth' => 1, 'container' => 'div', 'container_class' => 'menu', 'menu_id' => false, 'menu_class' => false)); ?>
by
<?php wp_nav_menu(array('theme_location' => 'Top menu', 'depth' => 1, 'container' => 'div', 'container_class' => 'menu', 'menu_id' => false, 'menu_class' => false)); ?>
Line 50, replace:
<?php wp_nav_menu(array('menu' => 'Navigation', 'theme_location' => 'Navigation', 'depth' => 2, 'container' => 'div', 'container_class' => 'nav', 'menu_class' => 'dd', 'menu_id' => 'dd', 'walker' => new extended_walker())); ?>
by
<?php wp_nav_menu(array('theme_location' => 'Navigation', 'depth' => 2, 'container' => 'div', 'container_class' => 'nav', 'menu_class' => 'dd', 'menu_id' => 'dd', 'walker' => new extended_walker())); ?>
I believe that it is not a good idea to specify the menu when calling wp_nav_menu in themes… Well to be honest, there is a possibility to modify polylang and not the theme (which might work for you) but I fear to break something else for other users…
In the file core.php in polylang/include/, line 267, replace:
if ($query->is_home && $this->curlang && !isset($qvars['post_type']))
by
if ($query->is_home && $this->curlang && (!isset($qvars['post_type']) || $qvars['post_type'] != 'nav_menu_item'))
and then go back to the line 234, just above the comment line
// sets the language for posts page in case the front page displays a static page
and add the following code:
// sets is_home on translated home page when it displays posts
if (!$this->page_on_front && $query->is_tax && count($query->query) == 1) {
$query->is_home = true;
$query->is_tax = false;
}
I will add these modifications (or better) to the next release.
Just for information… I did my first test with WordPress 3.3 and your theme looks broken… So take care when you will update. I hope that the theme will be updated. Everything should be OK with WordPress 3.2.1 with which I tested the modifications proposed above.