How to disable and enable next buttons

Hello, 

I would like to have a next button disabled until the timeline reaches a cue point. Then it becomes enabled and a user is able to click to advance to the next slide. I have accomplished this through creating a trigger to change the state of the next button to disabled when the timeline starts for each slide. And then a trigger to change the state of the next button to normal once timeline reaches the cue point. My issue is when revisiting the slide. If I select Automatically decide or Resume initial state, when the user returns to the slide, the have to wait until the timeline gets to the cue point again. If I choose Resume Saved State, the button remains disabled. Is there away to have the button enabled upon revisiting slides? 

Thanks for your help, 

Jessica