Can't get a layer to show when hovering (triggers)

Hey Rochelle, the layer properties are set to "Hide objects on the base layer" - which I think is where the problem lies. Since the hover items themselves (the rectangles) are on the base layer, this trigger action sort of cancels itself out... the hover item can't become invisible because it's actually the basis of the trigger. What you might try instead is changing your layer properties so that base layer objects are still visible, but create a semi-transparent rectangle behind the layer objects, to sort of gray out the base layer but stilll make it possible for the learner to see the rectangles they're hovering over. Slide 1 in the attached file is an example.

Another alternative is to use Markers to contain your hover content instead. This is an easy way to display supplemental text. You could insert a marker and customize it as "display all on hover", like in the second slide in the attached example. 

Each of the layers that appears are set to hide the base layer. This causes your button to lose "mouseover" which reverts back to the original state. If you deselect each "hide objects on base layer" it'll fix that. You might want to consider showing your buttons at the bottom of the slide, below the layer overlay and adding a background shape to each layer to obscure the stuff behind. 

Here's my take on how you might choose to tackle it.

Thanks so much to both of you for these quick, helpful responses!  I ended up adding a shape behind the content of each layer, and making the fill white, which masked all of the base layer content except the buttons, which was the effect I was looking for.  I'm definitely going to include the markers in future projects as well.