In role_teacher model, individual students can see their own comments but also teacher's ones, whereas individual students' comments cannot be seen by students.
input.btn {
color:#050;
font: bold 84% 'trebuchet ms',helvetica,sans-serif;
background-color:#fed;
border: 1px solid;
border-color: #696 #363 #363 #696;
filter:progid:DXImageTransform.Microsoft.Gradient
(GradientType=0,StartColorStr='#ffffffff',EndColorStr='#ffeeddaa');
}