Pomodoro Clock: feedback

What do you think about my Pomodoro clock?
Are there any bugs in it? How can I improve it?

The session and breaks times should a a minimum be 1 minute. Your clock allows setting both to 0 minutes, which is pointless. Plus, if you set your session and break times to 0 and click the Start button, you will get some strange behavior.

I fixed it. Anything else?