Hi NJ
It cannot be explicitely for CAPA, but entire header across application can be changed by changing the panel -header
.x-panel-header {
color:#333;
border:1px solid #d0d0d0;
background-image:url(ui/ext/gxt/tngtheme/images/gray/panel/white-top-bottom.gif);
}
regards
Suman Pramanik