Coupon Settings Custom HTML Question

Theme Setup/General Setup/Coupon Settings

Coupon button type is set to open (for the pop up box)

As you can see in my screen shot attached there is a custom HTML box, I assume that this is to insert text/shortcodes that I want to display in the pop-up box.

I want the excerpt to show, I think we need to show the terms of each deal/coupon in the popup and this seems to be the best way. The only problem is, nothing I put in the custom HTML box displays on the pop-up box?

Is this broken or is it actually for something else?