How can I hide this custom slider while Elementor editing window is open?

I was able to solve this with help from support at Smart Slider. They pointed out that the div that wouldn’t go away was using absolute positioning and suggested that I add an id to it so that I could then hide it using CSS. I did this by echoing an id name in header.php in the same line where I echoed the shortcode:

<?php 
        if (is_front_page() ) 
            echo '<div id="front-page-slider"' . do_shortcode('[smartslider3 slider="3"]' . '</div');

        else 
        { }
        # do nothing ?>

Then I had a new id of ‘front-page-slider’ to work with. I could then call that id in the JS I was using to hide the element:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
        <script>
        $(window).scroll(function() {
            var y = $(this).scrollTop();
            if(y > 250) {
                // $('.n2-ss-slider').slideUp();
                $('#front-page-slider').slideUp();
            }
            if (y < 250) {
                // $('.n2-ss-slider').slideDown();
                $('#front-page-slider').slideDown();
            } 
            if(y+ $(this).height() == $(document).height()) {
                $('#front-page-slider').fadeOut();
            }
        });
        </script>

and my problem was solved.