Hi
*Issue:*
When a user tries to select start and end time using the calendar, the
calendar gets hidden and inaccessible to the user.
*Solution:*
Set `Backform.DatetimepickerControl` option `widget positioning > vertical`
to `bottom` which ensures Datepicker widget expands to bottom whenever it
is opened.
Please find attached patch and review.
Thanks,
Surinder