I'm assuming that this is for CRM/Report/Form/Activity.php...when I modified this, it didn't change the default Activity dashlet, but instead changed the customized Activity report I set up (with the checkbox checked to allow use as a dashlet -- follow me??).
I'd like to change the default Activity dashlet...any idea which file to hack? This is difficult to determine when using AJAX.
CRM/Dashlet/Page/Activity.php doesn't seem to be the one, either.