Seems, it is executed “home” key, no “back” key. Back key is processed like a right mouse button (because many manufacturers created mice which sends back button if you press right mouse button). If you jump to home screen then probably is send “home” key.
Well, this is a bit complicated, but maybe can be solved. There is problem, similar to back button, many manufacturers send home button for a “middle button”. Do you press middle button on the mouse? Can you send me email? I like to get more information.
Regarding second question – just now it is not possible, it was implemented in the past, but at one point was support for samsung s-pen and physical mouse rewritten from the scratch and this feature was dropped. The old code is completely incompatible with that how it works now. But maybe I can check it and if it will be not hard then I can add it again.