hideactivitiesview() // call under onload of xrm page; comes in default script of this file

function hideactivitiesview()
{
  var viewSelector = $('#crmGrid_SavedNewQuerySelector')[0];
  if(viewSelector)
  {
    $(viewSelector).click(function(){
      var _activity = $('#ViewSelector_activity')[0]; //get this id from DOM using F12
      if(_activity)
        $(_activity).hide();

    });
  }
}