Datetimepicker min max values

### Issue type

**I'm submitting a ...**

* [x] bug report
* [ ] feature request

### Issue description
2 datetimepickers:
- first one to select a datetime
- second one has in min value the first datetimepicker value

**Current behavior:**

Second datetimepicker sets minimum datetime to next day (except when 0:00)

**Expected behavior:**

Same day should be selectable (maybe set minimum in time picker)