Using Layers

Hi

I have made a course in Storyline and am using layers on a slide, so that learners can click on a button for a year, and see what happened that year.

The buttons (and layers)  start in 1983 and there are 7 layers ending in 2012.  My problem is that when I preview it, and click on the 1983 button, it goes to that layer, but the other year buttons do not function as a hyperlink.  If I go back to the Layer slide in my course, I can click on each of the buttons and they function fine.

Can someone please tell me why the first layer is not functioning as I am intending.

Thanks.  I hope this question makes sense