Content Management and Capture

In ICN when viewing documents in a ContentViewer feature, if I right click on one of the document tabs I get a menu with the option of "Close".  Can I add to that menu through a custom plugin or js api?  I've been looking all over for the right object or method to manipulate, but haven't found it so far.

#IBMContentNavigator(ICN) 

Never mind I figured it out.  I have to extend PluginMenu with a type of ViewerTabContextMenu and link the added menu items as PluginActions.