Click outside thumbnail-wrapper in order to close it

I’m trying to achieve an additional feature: If the user clicks out of the thumbnail-tray-div, it should disappear resp. move to the bottom.

This should be the relevant code (supersized.shutter.min.js)

a(vars.thumb_tray).animate({
    bottom: -a(vars.thumb_tray).height()
}, 0);
a(vars.tray_button).toggle(function () {
    a(vars.thumb_tray).stop().animate({
        bottom: 0,
        avoidTransforms: true
    }, 300);
    if (a(vars.tray_arrow).attr("src")) a(vars.tray_arrow).attr("src", vars.image_path + "button-tray-down.png");
    return false
}, function () {
    a(vars.thumb_tray).stop().animate({
        bottom: -a(vars.thumb_tray).height(),
        avoidTransforms: true
    }, 300);
    if (a(vars.tray_arrow).attr("src")) a(vars.tray_arrow).attr("src", vars.image_path + "button-tray-up.png");
    return false
});

Any help how to achieve this would be awesome. Thanks in advance.

https://www.ads-software.com/plugins/wp-supersized/