Light boxes on the player are not accessible

Hello,

I have a player tab created called "Keyboard shortcuts". It is part of the player so you can click it at anytime during the course. When the user click it, it opens a slide as a light box. However, a screen reader won't read the content on the slide. It displays it, It just won't read it on the screen reader. All the screen reader will read is the Slide title and the close button. 

Is this working as intended?