Menu location option not checked after page refresh

Overview of the issue

When creating a menu and assigning it to a location in Appearance → Menu, refreshing the page unchecks the location checkbox. However, the menu still displays correctly on the front-end.

This issue occurs when term IDs are not equal to term taxonomy IDs, which can happen on sites running WordPress since version 4.1 or older as explained here.

Workaround

Please, be sure to make a full backup of your site before proceeding.

1. Open …/sitepress-multilingual-cms/inc/taxonomy-term-translation/wpml-term-translation.class.php.
2. Look for line 118.
3. Change:

   	private function maybe_warm_term_id_cache() {
   
   		if ( ! isset( $this->ttids ) || ! isset( $this->term_ids ) ) {
   
   			$data           = $this->wpdb->get_results( "	SELECT wpml_translations.element_id, tax.term_id, tax.taxonomy
   													 " . $this->get_element_join() . "
   													 JOIN {$this->wpdb->terms} terms
   													  ON terms.term_id = tax.term_id
   													 WHERE tax.term_id != tax.term_taxonomy_id",
   			                                      ARRAY_A );
   			$this->term_ids = array();
   			$this->ttids    = array();
   			foreach ( $data as $row ) {
   				$this->ttids[ $row['term_id'] ]                     = isset( $this->ttids[ $row['term_id'] ] )
   					? $this->ttids[ $row['term_id'] ] : array();
   				$this->ttids[ $row['term_id'] ][ $row['taxonomy'] ] = $row['element_id'];
   				$this->term_ids[ $row['element_id'] ]               = $row['term_id'];
   			}
   		}
   	}
   

   To:

   	private function maybe_warm_term_id_cache() {
   
   		if ( ! isset( $this->ttids ) || ! isset( $this->term_ids ) ) {
   
   			$data           = $this->wpdb->get_results( "	SELECT wpml_translations.element_id, tax.term_id, tax.taxonomy
   													 " . $this->get_element_join() . "
   													 JOIN {$this->wpdb->terms} terms
   													  ON terms.term_id = tax.term_id
   													 WHERE tax.term_id != tax.term_taxonomy_id",
   			                                      ARRAY_A );
   			$this->term_ids = array();
   			$this->ttids    = array();
   			foreach ( $data as $row ) {
   				$this->ttids[ $row['term_id'] ]                     = isset( $this->ttids[ $row['term_id'] ] )
   					? absint($this->ttids[ $row['term_id'] ]) : array();
   				$this->ttids[ $row['term_id'] ][ $row['taxonomy'] ] = absint($row['element_id']);
   				$this->term_ids[ $row['element_id'] ]               = absint($row['term_id']);
   			}
   		}
   	}