Hi,
I have some issue on 4.3-rc2, it’s certainly a mistake 
but I can’t figure it myself.
I created an AppVM, in its Settings → Advanced I set “Disposable template”. But from the menu in “Apps” tab, when I start my qube, it’s not named “disp…” something.
If I type qubesdb-read /qubes-vm-persistence the result is rw-only, so it’s clearly the disposable template and not a disposable started from it…
In the Qubes menu, the default default-dvm starts new disposables named “dispXXX” as expected.
Since I opened “default-dvm” settings and clicked on apply, it seems it does not start as disposable anymore too, maybe something is wrong in the settings? 
I figured it out. From the Qubes menu in dom0, if you start a qube with “Start qube”, the template starts, but if you click on an application then it starts a nameless disposable.
There are a number of subtleties involved with the distinction between an appvm you intend to run, one that is used as a template for disposables, and even differences when dealing with disp-1234 disposables versus named ones. Mostly involving the menuing.
I finally got my automated install stuff to correctly handle all three cases after a lot of struggle.