So I’m just giving it a try. Nice functionality, but if the only place I can have the button to expand it is stuck in front like that, a lot less useful. I’m looking to either customize where it shows up, or get rid of the default one entirely and put in a button of my own that does the same thing, whichever lets me put it where I want it.
I had started by trying to make the menu bar I wanted the button in a child of Header. By using an overlay to hold said bar and the expandable area, I was able to just use padding to move the header around. Marking solved and leaving for posterity’s dubious benefit 
One other solution that worked for me. Set the default arrows (Collapsed and Expanded Image) found in the style section of the expandable area to an image size of 0 to hide them. Then add a horizonal box under the Expandable Area > Header. You can then put an image in the horizonal box and customize it as needed.
