Datepicker incorrectly shown during alt tab

When you change the value of an input (that has a date picker) in the blur event, the date picker is suddenly shown and shown at an incorrect position when you put the focus back on the input using the alt tab key combination.

This happens in both internet explorer as firefox (didn't test other browsers).

This bug is introduced in version 1.8.7 but still exists in version 1.8.9.

In version 1.8.6. it runs as expected.

The following shows the code:

$('input.date')
 .datepicker(
      { dateFormat: 'dd/mm/yy', showOn: 'button', 
        buttonImage: 'Images/calendar.gif', buttonImageOnly: true 
  })
 .blur(function(event) {
   var target = formGetJavascriptEventTarget(event)
   jqTarget = $(target);
   jqTarget.val('1/1/2000');
});