Twentyfifteen Theme

Submenüs offen halten

Folgender CSS-Code in die style.css

.main-navigation li ul {
    display: block;
}

Quelle: https://forum.wpde.org/threads/twenty-fifteen-menues-geoeffnet-lassen.140560/

Navigation Buttons (Pfeile) entferen

button.dropdown-toggle {
    display: none;
}