Don't hide jQuery UI's datepicker when selecting a date [duplicate]

This question already has an answer here:

• jQuery Datepicker: Prevent closing picker when clicking a date 9 answers

I'm using jQuery UI's datepicker for a custom form, and I'm trying to keep the datepicker dropdown open even after selecting a date.

My code currently looks something like this:

$('#datepicker').datepicker({
  numberOfMonths: 2,
  showOtherMonths: true,
  selectOtherMonths: false,
  nextText: "",
  prevText: "",
  onSelect: function() {
    $('#datepicker').val('Custom');
  }
});

I was looking through the API documentation but wasn't able to find anything helpful.

As always, any kind of help will be much appreciated!