How to make WP dropdown menu always open?

Question

User navigation

1) Menu items - they have child items (by default they are not expanded) ------ so they are now
2) Menu items - they have child items (by default they are expanded everywhere and always) ------ need make
WordPress Twenty Fifteen theme
Who knows how to open forever - poke, please...

Answer 1

.menu li > .sub-menu > ul {
display: block;
}