The following is an example of a new content definition named myexistingTabAction:
<content-definition>
<id>myexistingTabAction</id>
<app-id>workspace</app-id>
<enabled-yn>true</enabled-yn>
<object-type>ContentDefinition</object-type>
<content-id>myexistingTabAction</content-id>
<mime-type>text/javascript</mime-type>
<body>atgChangeTab(atg.svc.framework.changeTab("DefaultTab"),
null, null, null);</body>
<url-yn>true</url-yn>
</content-definition>
