You're right, the melody notes really do stop, and it was unintentional. Recently reworked most of the core (due to variable BPM) and this is a collateral damage. I quite like it, so it will become an option/setting

Also, that particular channel plays probably the longest song of them all - it looks like it overruns the receive buffer... thanks for the heads up!
The score editor in the app is currently undergoing major upgrades - there will be more than one keyboard layout, to make it easier for people who play something else than the piano...
Rests and pauses aren't there yet, I remember you suggested it. To make keyboard activity clear and more versatile, there will be a switch to either put text directly or to "play" on it with all the required extra notation put down automatically.
So, perhaps the implementation gap... hope to close it soon in the way that doesn't end up with two smaller gaps

Thanks again for your great feedback.