Per http://lmms.io/forum/viewtopic.php?f=7&t=1421&p=5900#p5900

I know this is a user problem, but it would be nice for the piano roll to be usable when its first opened, like the BBEditor is by simply defaulting to the first relevant track. If not, the piano-roll button should probably be grayed out until at least one piano roll has been created.