Next button not enabling - Using variable

Please see attached sample file. 

I want to be able to lightbox a video and have the next button enable after user views video (selects button to lightbox the slide). Is this possible lightboxing the video or does it need to be on a layer?

The variable is firing.

I have not had success figuring this one out. I greatly appreciate your ideas.

Slide One:

Disabled next button when timeline starts.

User selects a button to view a lightboxed video.

Created T/F variable for lightboxed video to change to true when timeline starts on the lightboxed slide.

Set trigger to change state of next to normal when the timeline starts on slide one if LightboxVideoViewed  = value True.

I've also tried it with the button 1 is visited AND LightboxVideoViewed = True.