What I want is two separate instances of Audacity running in parallel as to separate programs with different settings.
I want one to use WASAPI as audio host and speakers as input device (the 2.0.5 portable has the WASAPI option), and the other to use the MME as audio host, and microphone as input device.
When opening a new (second) window of the same installation/copy of Audacity, by executing twice the .exe file, it is the same as giving the command 'new' under 'File', what happens is not a second instance, but just a separate project/file and window. When settings are changed in one, they change exactly in the other.
When trying to start a second copy of Audacity, or even a second different version, when one is already running, it will also open just a second project/file of the application that is already running, as before.