TimePicker control will display as empty if its initial value is set to 12:00AM
Since version 4.0.0, when you initialize a time picker to start with the value of 12:00AM it will display the format instead of the actual value (for example hh:mm:ss AM, where 12:00:00 AM should have been displayed).
I forgot to mention that, I think, this only happens when you have set the initial time to today's 12:00AM, if your initial value is 12:00AM of another day, then it displays correctly (updated the demo to demonstrate this)