The default date was first day of the month when skipping selecting date

This happened when:
- User switch to time view without picking a date
- viewMode was "time" and user selected time without picking a date.

I'm not sure whether this is a bug or not but it makes more sense if the default date is today.

My scenario is most of the time users just need to select a time but they are allow to change the date when they need. And also, default value is not allowed for preventing user from skipping the input.

Now I'm using onFocus to set default date as a workaround.