There may be two issues here. The first is that it seems that the widget can become disconnected from the status of the program so that it doesn't show the program running when it is, won't respond to clicks, etc. Removing it from the dashboard and then adding it again from the tray seems to get it back on track.
Second, the whole widget seems to be a hot area. Its really hard to tell what is clickable about it, what isn't, and what clicks are actually doing. Hard to distingush the clicked pause and arrow from unclicked, certainly until you've seen both states. Also, opening the pulldown seems to frequently start up a session. I think problem 2 is what got problem 1 started - i.e. in clicking around on it trying to figure it out, I got the widget hung up somehow.
Generally, very very cool idea. Being able to run that from a widget is super. Just behavior is a little wonky.