Reported for: WPML Multilingual CMS 3.3.6
When adding a link to a post or page, an ajax request is being sent in order to get all other posts that you can link to.
This request calls cause a fatal error as such:
Fatal error: Call to private method WPML_Language_Resolution::get_referrer_language_code() from context 'SitePress' in wp-content/plugins/sitepress-multilingual-cms/sitepress.class.php on line 2328
The WPML 3.3.7 will contain the fix.
Meanwhile, to solve the issue in your current version, go to
sitepress-multilingual-cms/classes/request-handling/class-wpml-language-resolution.php and then on line 92 change this code:
private function get_referrer_language_code()
public function get_referrer_language_code()