I bought the full version expecting the top panel to start working, but it didnt. Furthermore, the app started to crush at start-up after I created a timer, which rendered it 100% unusable.
I sent a message to support e-mail (which I had to dig out of the developers website), but got no response in 5 days.
To sum it up, $1 wasted on the app purchase + about an hour on trying to make it work and contacting support - all in vain.
Cervus1983 about Interval Timer Pro, v1.3