I have a weird issue, it seems like the intended behaviour for when you set “advanced->disposable VM template” on an app-vm is that it should populate a new entry in the app-menu where you can launch the disp vm’s. Although on my system that does not happen, and I have no clue as to where to start to troubleshoot it.
If i create a new app-vm, those appear in the menus fine.
Happens sometimes.
Try this:
qvm-features <dvm-template-name> appmenus-dispvm 1
Unfortunately that did solve the issue, tried logging out and back in again but no new entry 
I think there may be some confusion.
You wont see a new menu: the question is what do the menu entries do?
If you open (e.g) firefox from that menu does it start a disposableVM?
shouldnt it create a disposable: entry in the meny?
And i just tried, starting a firefox still only starts the app-vm and does not spawn a new disposable. Very weird.
As a workaround I was able to clone the whonix-ws dvm machine, change template to fedora-32 and change net-vm. Then it added a disposable: entry and it seems to work as intended.
That is very strange. When you tick the “disposableVM Template” box all it makes when you click an application shortcut for that AppVM is start a dispVM instead with the the AppVM’s private file system and the TemplateVM’s root as a base.
I don’t think I’ve ever been able to make a DVM with Qubes manager and changing settings there breaks them. The instructions in the documentation here work most of the time: Creating a new DisposableVM Template