Scrolling Text Learning Interaction widget layering isssue

I have not found any threads similar to the issue I am experiencing.

I have implemented a fix from this post: Captivate 9.0.1 - web object z-order because I needed to be able to have objects on top of Web Objects in my project (otherwise, Web Objects are always placed on top of everything, regardless of layer order in the timeline).

Now I am also using a Scrolling Text Learning Interaction widget. I am trying to put a simple shape background behind it, but this seems to disable/block the scrollbar on the widget in HTML5 output. If I remove the background shape, the widget scrollbar functions properly. I made certain that they are layered appropriately in the timeline. I have tried to use javascript to change the CSS z-index in HTML5 output, but that's not working either. It works fine in Flash output.

Is it likely that the same solution that fixes the z-order of the Web Objects is affecting the layering ability of the Scrolling Text widget? I can't really think of another way to place a background behind the Scrolling Text widget (it overlays a video, so needs to have a background for the text to be readable).

Any ideas are appreciated.

Thanks,

j