virtual midi keyboard not working

[joachimheintz]

as reported on the csound mailing list (9 january), the virtual midi keyboard does not work currently.
the keyboard shows up, and the keys react when being clicked, but no sound.
for instance in steven's example: https://ide.csound.com/editor/eFYG0gBxPzx4dU6u7Mxc

[Nandos0804]

Tested on production:

Adding

<CsOptions>
-M0
</CsOptions>

invokes the prompt for midi support on Browser and it is possible to use the Virtual Keyboard.