$(document).ready(function() {
  $('#btn-researchgroups').click(function(){
    if ($('#shelf').is(':hidden')) {
      $('#shelf').slideDown(500);
      $('#btn-researchgroups span').addClass('minus');
    } else {
      $('#shelf').slideUp(500);
      $('#btn-researchgroups span').removeClass('minus');
    }
  });

  $('#collapse-groups').click(function(){ 
    $('#shelf').slideUp(500); 
    $('#btn-researchgroups span').removeClass('minus'); 
  });

});