Hi Chris,
The problem with the code the action builder generates is that it is based on the exit event of the GrantTotal field. It does work but you have to select all checkboxes to get the value of 400 and then you have to tab though the GrandTotal field so the exit event if triggered.
Try removing the GrantTotal.exit event from action builder and change your calculate event to something like;
var total = parseInt(CheckBox1.rawValue) + parseInt(CheckBox2.rawValue) + parseInt(CheckBox3.rawValue) + parseInt(CheckBox4.rawValue);
if (total ===400)
{
Button1.access ="open";
}
this.rawValue = total;
Regards
Bruce