Hi,
Could it be that this is the same project as this one ?
Widgets don’t send a message when they receive one, but you can make O-S-C reply using a custom module, here is a small example that demonstrate this. If I guessed right and the aforementioned post is related to your project, you’d just need to amend your code so that along with the receive() calls that update the interface some send() calls ensure replies are sent:
send('midi', 'my_osc_device', '/control', channel, ctrl, value)