Hi Grrrr and svmcwd,
as mentioned in the manual , page 40 , section 4.1.4.3,
yes you can still play with the muted parts, there is a setting for this, available in MIDI CONTROL CENTER, in device settings panel.
this setting is called mute/solo : toggle or latch mode.
default setting is on TOGGLE, as you both noticed, when pressing mute, you can mute tracks
if you set it on latch, activating mute (or solo) will give you the ability to freely play on muted parts. you enter mute, select the tracks you want to be muted. Then if you press mute again, mute button will blink, instruments will be muted , but you can freely play with them.
No hardware shortcut for this, therefore i strongly recommend that you install the MIDI CONTROL CENTER, if not already done.
you can get the MIDI CONTROL CENTER here :
https://www.arturia.com/support/updates&manualshope this helps,
best,