Greg, there is actually already an issue that partially touches on the
topic
https://github.com/MarcusWolschon/osmeditor4android/issues/435
But actually I suspect your functionality would be covered by a simpler
"previous layer" function (a la "prev channel" on TV sets), which would
be simple enough to do, but likely would have to be in a menu as we
don't really have a good place to put it on screen right now. I'm
playing with the idea of adding a drawer of sorts with the most used
menu items, but that isn't likely to happen short term.
Simon