Advanced Designed Wont Let Me have Transparent Background And Frame!

When trying to use the advanced designer, when I use the color wheel to go to transparent, it just defaults to white! 

My other forms in the past are fine, but any new ones wont let me do transparent. 

I've checked this on my end and I can see it works fine, when I select a transparent background color it's saving properly: 

However, you will notice the transparent background when you embed the form or when you change the page to another color. Additionally you could inject this CSS code to your form to ensure the iFrame color is transparent: 

.supernova{

    background-color: rgba(0,0,0,0);

}

Guide: How-to-Inject-Custom-CSS-Codes

Hope this helps.