MIDI Loop Recording - multiple takes in layers. How does this work?

With hardware synths, you can just mute the MIDI track, and only the live input on each take will be echoed, but this doesn't work with soft synths because muting the MIDI/Simple Instrument track mutes the audio output as well.

The workaround for soft synths is to assign a second MIDI track to the synth, leave input echo disabled (and/or keep the focus on the other MIDI track if Always Echo Current MIDI Track is enabled in Preferences), and record on that second track. The first track will echo the live input, and the second track will record new takes without sending anything to the synth until you play it back.