Dropdown menu VS. Artboard Height in Prototyping

Hey there.

I have an issue that has been driving me nuts for a long time.

I'm designing a little dropdown screen with some hidden info that I am auto-animating.

Everything works well, but in order for it to work I have to have a much taller artboard than I would ideally like to have.

The first image is with the menu item Gig Poster collapsed. The second is with it expanded.

The third image is the space at the bottom that I have left for everything to still fit in my screen when menu items are expanded.

Is there any way to avoid this space? Not sure of the right word - adaptive or dynamic artboard height, that will adjust to the content that is exapanded. 

My problem is that I want to design all the menu items to function, and that results in a very tall artboard which, when all items are collapsed, the user will be able to scroll through and see empty space.

Many thanks in advance,

Nick