If you encounter weird placement of the triangle next to sub menus as soon as you hover them (see this screenshot), add the following CSS code to your site (e.g. by using Simple Custom CSS).
.blog-menu ul > .has-children:hover::after,
.blog-menu ul > .page_item_has_children:hover::after { border-left-color: #FFF; border-right-color: transparent !important; }