Jumping header on scroll using jQuery Waypoints

Question

I have fixed bootstrap menu on the top of the page and an asbolutely positioned scroll button .btn-navigate at the bottom of the viewport (in #home-slide). On (any) scroll, I want the fixed menu to change background from transparent to semigray and also the scroll button to disappear. The button should keep on being hidden from now on, but when I scroll to the top, I need the menu to become transparent again.

For this purpose I am using jQuery Waypoints. I have achieved both effects using the following code, but when I scroll, the menu jumps, EDIT: More specificaly it flashes as if the menu is not at fixed position all the time. When I scroll, it sometimes look as if the menu scroll out with the page and then suddenly jumps back in the fixed position. Sometimes after a while is starts to work correctly. It s not jumping if I remove the following two lines of code, but I need the same trigger for both events.

EDIT2: It is also not flashing if I don't use waypoints with the menu. The scrolling is smooth and the menu is always atop of all other elements in the page.

 $("#home-slide .btn-navigate").removeClass("pulse animated");
 $("#home-slide .btn-navigate").addClass("fadeOutUp animated2");

HTML:

<header id="masthead">
    <nav class="navbar navbar-fixed-top">
        <div class="container">
            MENU CONTENT
        </div>
    </nav>
</header>
<section id="home-slide">
    <div class="container">
        <h1 class="heading">HEADING</h1>
        <p class="font2">
            TEXT</p>    
        <a href="#" class="btn-navigate animated pulse">Scroll Button</a>
    </div>
</section>

jQuery:

jQuery(document).ready(function ($) {
    $(function () {
        $("#masthead nav").waypoint(function () {
            $("#masthead nav").toggleClass('scrolling');
            $("#home-slide .btn-navigate").removeClass("pulse animated");
            $("#home-slide .btn-navigate").addClass("fadeOutUp animated2");
        }, { offset: '-20px' });        
    });
});

MY Navigation CSS:

#masthead {

    nav {
        min-height: 120px;
        padding-top: 2.727rem;
        background: rgba(51,58,64,0.0);
        -webkit-transition: background-color 0.5s linear;

        .container {
            position: relative;
        }

        .navbar-nav {
            a {
                color: @lms-white;
                font-weight: bold;
                text-transform: none;
                text-shadow: 1px 1px 2px rgba(50, 50, 50, 1);
                padding: 7px 1.17rem;
                border: 2px solid transparent;
                .border-radius(5px);

                &:hover {
                    background: transparent;
                    border: 2px solid @lms-pink;
                }
            }
        }

        .navbar-brand {
            padding: 7px 15px;
        }

        &.scrolling {
            background: rgba(51,58,64,0.9);
            -webkit-transition: background-color 0.5s linear;
        }
    }

Bootstrap Navigation CSS:

.navbar-fixed-top {
    top: 0;
    border-width: 0 0 1px;
}

.navbar-fixed-top, .navbar-fixed-bottom {
    position: fixed;
    right: 0;
    left: 0;
    z-index: 1030;
}

.navbar {
    position: relative;
    min-height: 50px;
    margin-bottom: 20px;
    border: 1px solid transparent;
}

Any idea how to solve this? Thank you!

Answer 1

I have found the solution. The blinking was not cause by Waypoints. Adding

-webkit-backface-visibility: hidden; /* Chrome, Safari, Opera */
backface-visibility: hidden;

to nav solved the problem.