Custom menu buttons

Hello all - 

I got to thinking about creating a custom menu button based on some things I'd seen here and other areas.   

Here's the thought I had - A small icon that the user clicks on, and it expands to show the course menu.  Click again and the menu goes away.  Easy peasy, i thought!

When I first built it, I just had the button click through to show another layer with the menu appearing.  I quickly realized that this would only really work if the slide only had that one layer.  If there were any other layers, the button would hide them when showing the menu.

So, then i tried to add it to the master slide, and it worked to a degree, but the slide's layer would overlap the master layer, and cover anything under it.

Last, I tried to put the menu in a Selected state, but again, it was covered up by any layers that were shown.

I guess my question is - is there a way to get the menu to always be on top while showing other layers?