Vincent Burel wrote:if firefox is present twice after a restart audio engine, it means it's alaso present twice in Windows Volume Mixer... please ask to Microsoft.
Yes, as I mentioned earlier, we can simply use sndvol32.exe to show that this is not a VM bug, it is a windows bug.
Or, strictly, it is a "feature" since it is working as intended, they just intend for it to work badly.
Still, we can talk to Microsoft but everyone knows they are not listening.... It took them TWENTY-FOUR YEARS to add the feature to assign default audio devices per-application,
and they still did it wrong, and still we have to pay for third party software to get re-routing.
Anyway, enough bashing microsoft, it is too easy
As OP says, the problem is that because of the duplicated entries, and even without that "feature" it is possible, that a list of applications using a device can become so long that it is not possible to see them all in the VM UI.
So, that is why we talk about workarounds from other applications such as showing playing streams instead of open devices, or of scrollable application lists.