STORYLINE LIGHTBOX BACKGROUND (MODERN PLAYER) NOT TRANSPARENT

Hi, fairly new to storyline after spending years with captivate.
Could someone please explain to me where these java triggers need to go/how to be triggered. I can't for the life in me get them to work.

I've tried both 
document.getElementsByClassName('lightBoxSlide')[0].style.backgroundColor = "transparent"

and
$(".lightbox").find("rect[id^='slide-bg']").hide();

using - execute javascript, when the timeline starts on this slide
and I've tried these on both the slide that is the lightbox and the master slide for that slide.

Neither have worked.
I'm trying to create a universal support slide for our courses (triggered from a support option on the player) have I done something wrong with the script or is it not supported when triggered from the player.

please help