tokens: I was able to fix it by adding border : 1px solid #B7DDF2 to the CSS of nav ( or .ui-menu ui-widget ui-widget-content ui-corner-all ) :
ner_tags: O O O O O O O O B-Code_Block I-Code_Block I-Code_Block I-Code_Block I-Code_Block O O B-Language O B-Code_Block O O B-Code_Block I-Code_Block I-Code_Block I-Code_Block O O