When an iframe is added to the background(advanced feature) it displays perfectly. However it appears that the <div class="slides"> is blocking all the input to the iframe. Im wondering if this is the intended functionality or if it would be possible to still interact with the iframe background.
We just revised how this works. From now on, you will be able to interact with a background iframe as long as the slide itself is completely empty. If there is slide content in the foreground, that will take precedence and prevent you from clicking through to the iframe background.
Hope that makes sense and thanks for the feedback!