Instant scrollbar position + absolute position elements

[GrupoWebex]

Checklist

• I'm using 0.4.3

Description

2 issues:

1. When i click on button, scrollbar go instant to position 0, so absolute position elements (parallax + main header) have a terrible visual effect.
2. Trying to skin bootstrapv4 + fontawesome, with custom css is not working on mobile (but is working on small resolution desktop browser). That maybe is my css fail:

`
$('body').scrollToTop({
skin: 'bootstrap'
});

//scrollToTop
.scrollToTop_bootstrap {
background-color: lighten($primary, 25%) !important;
border-radius: $border-radius;
z-index: 9999;

@include hover{ background-color: $primary !important; }

&:after {
font-family: "Font Awesome\ 5 Pro";
content: "\f341";
font-size: 30px;
position: absolute;
right: 64px;
top: 3px;
color: #fff;
}
}`

What did you expect to happen?

1. progressive scrollbar position.
2. i should see button contents on mobile device