Variables not keeping data

Hi,

I'm having an issue with variables not keeping data when jumping scenes. 

I've created a slide where the user reads a short description about a topic, once finished they will have to click the preview button which will direct them to another scene timeline.  

First slide I have a continue button which acts as a next slide with a variable (DPRAW with a value of 1) now that button is hidden when timeline starts with a condition of (if DPRAW is equal to 1). So when the user clicks the button preview I added a trigger which subtracts a value of 1 to DPRAW which will allow the continue button to appear. 

When you click on preview button the user is directed to another scene where the interactive interface is and then they can click a close button which will direct them back to the original slide.

The issue I'm having is when the user returns back to the original slide the variable doesn't change. Is this due to the different scenes, as variable don't work when changing scenes?

If you need a better explanation please let me know.

Thanks,

Seb