Using setDate on another input changes datetimepicker focus to other input

[midnightmonster]

This is probably related to #56, but I have two datetimepickers, one for the start of an event, the other for the end. When the date/time is selected on the first one, I want to also set the second one to one hour later.

var $start = $('input[name=begin_dt]');
var $end = $('input[name=end_dt]');
$start.datetimepicker({
  onSelect:function(){
    var date = $start.datepicker("getDate");
    date.setHours(date.getHours()+1);
    $end.datepicker("setDate",date);
  }
});
$end.datetimepicker({});

With this code, focusing the first field and setting the date causes the second field also to be set to one hour past the first field value, but the 'Time: X:XX' display makes a visible jump to momentarily show the second time before switching back to the first time.

That was setting the date only. If I then use a time slider (or use a time slider before changing the date), as soon as I let go of the mouse, the first and second field are both set correctly, but the datetimepicker immediately becomes associated with the second field instead of the first: the time switches to the 1-hour-ahead value, and all changes to date or time until closing the widget affect the second field instead of the first. The location of the datetimepicker does not change.