Same issue, was doing an empty() check on $page_urlname in Admin:PageManager and not taking both main pages into account
#frmbody {
padding: 10px;
background-color: #FFF;
border: 1px solid #CCC;
}
.frmRow {
margin-bottom: 10px;
}
#templatesrc {
border: none;
width: 320px;
height: 240px;
}
.title {
padding-bottom: 5px;
}
.mceActionPanel {
padding-top: 5px;
}