Hi there,
generate_menu_bar_items
will be added to the list in the next GPP updated.
In the meantime you can select Custom Hook and generate_menu_bar_items
to the field provided.
That hover effect is from CSS in your Customizer > Additional CSS.
This part controls the hover element:
.main-navigation .menu>.menu-item>a:hover::after,
.main-navigation .menu>.menu-item>a:focus::after,
.main-navigation .menu>.current-menu-item>a::after {
width: 40px;
/* controls the width of the line */
color: #ffffff;
}
This line needs:
.main-navigation .menu>.menu-item>a:hover::after,
needs to be:
.main-navigation .menu>.menu-item:hover >a::after
This way the hover is detected on the larger LI element and not just the link text.