Custom websites, created before Feb 9 2016, don't support external links in the menu
To add this funcionality, is necessary to modify some portions of code in the header.jsp file. Find this code:
<li>
<a data-id="<%=item.getId()%>" data-type="<%=item.getType()%>" href="<%=item.getLink()%>" target="_self">
<%=item.getLabel()%>
</a>
</li>
And replace it with:
<li>
<%
String link = item.getLink();
if(!link.startsWith("http://") && item.getType().equals("LINK")){
link = "http://" + link;
}
if(!item.getType().equals("LINK")){
link = "/" + link;
}
%>
<a data-id="<%=item.getId()%>" data-type="<%=item.getType()%>" href="<%=link%>" target="_self">
<%=item.getLabel()%>
</a>
</li>