This came up on this thread and figured I would post something about it is an easy mistake. The Finesse layout is devided into an Agent and Supervisor section. So adding a tab to the top of the default layout will only add it to the Agent view. You can tell the layouts apart by the following tags:
<layout>
<role>Agent</role>
<page></layout>
or
<layout>
<role>Supervisor</role>
<page>
</layout>
~david