Mystery loss of focus in Storyline embedded in Rise

Hi,

I have a Storyline item that is embedded in Rise. It contains two iframes that have content that is not keyboard accessible, so I have used tabindex ="-1" to prevent them from being included in the focus order. I have also removed the iframes from the focus order in Storyline. The only interactive element on the first slide is a button with a trigger light-boxing a keyboard navigable version of the iframe content (a video showing how the iframes behave). There are two non-interactive text labels, but I have tried removing them and it makes no difference to the behaviour of the Storyline. I have all player controls turned off.

The issue I am seeing is that when a keyboard user tabs into the Storyline, they are able to open the lightbox with no problem as the button immediately gets focus and shows the focus rectangle. However, when they try to tab out of the Storyline and continue with the rest of the Rise module, focus disappears and it takes three "silent" tabs before it reappears in the next Rise element. I have tried different iframe content but this makes no difference. Deleting the iframes makes the Storyline behave as expected and tabbing onward from the button immediately returns focus to Rise. I have also tried embedding the Storyline in Blackboard, and the same issue occurs - it seems to be a Storyline rather than a Rise issue.

Any help would be much appreciated!

Best wishes

Richard

University of Manchester