Thank you for putting together an application that defaults to requiring me to opt in to notification sounds. This is the first time I've seen a sensible default to such a feature. Additionally, the fact that I don't have to wait several annoyingly long seconds for the tooltips to appear on the buttons in this application is a welcome aspect as well. A lot of app developers can learn from this application's non-annoying design.
It could be slightly smoother moving the columns around -- but otherwise, this app appears great.