SYMPTOM:
In Strategy Web 9.4.1, the following error message appears when selecting a hierarchy as selector in a document:

The Web Server encountered an unknown runtime error. Can not add control to the template unit of type 2.
<record reset="true"> <package>com.Strategy.web.controller</package> <level>SEVERE</level> <miliseconds>1398711574165</miliseconds> <timestamp>04/28/2014 14:29:34:181</timestamp> <thread>0</thread> <class>GenericWebAppController</class> <method>processRequest</method> <message>Can not add control to the template unit of type 2 (com.Strategy.utils.MSTRUncheckedException)</message> <exception>com.Strategy.utils.MSTRUncheckedException: Can not add control to the template unit of type 2 at com.Strategy.web.objects.RWGridGraphDefImpl.addControl(Unknown Source) at com.Strategy.web.objects.RWGridGraphDefImpl.addControl(Unknown Source) at com.Strategy.web.beans.RWEventHandlerImpl.getRWSelectorControl(Unknown Source) at com.Strategy.web.beans.RWEventHandlerImpl.handleAddControlToGrid(Unknown Source) at com.Strategy.web.beans.RWEventHandlerImpl.processRequest(Unknown Source) at com.Strategy.web.beans.GenericEventHandler.handleRequest(Unknown Source) at com.Strategy.web.beans.AbstractWebComponent.handleRequest(Unknown Source) at com.Strategy.web.beans.GenericEventHandler.delegateRequest(Unknown Source) at com.Strategy.web.beans.GenericEventHandler.handleRequest(Unknown Source) at com.Strategy.web.app.beans.RWFrameEventHandler.handleRequest(Unknown Source) at com.Strategy.web.beans.AbstractWebComponent.handleRequest(Unknown Source) at com.Strategy.web.beans.GenericEventHandler.delegateRequest(Unknown Source) at com.Strategy.web.app.beans.PageEventHandlerImpl.delegateRequest(Unknown Source) at com.Strategy.web.app.beans.PageEventHandlerImpl.handleRequest(Unknown Source) at com.Strategy.web.beans.AbstractWebComponent.handleRequest(Unknown Source) at com.Strategy.web.app.beans.RWPageComponentImpl.handleRequest(Unknown Source) at com.Strategy.web.app.beans.ServletEventHandlerImpl.processPage(Unknown Source) at com.Strategy.web.app.beans.ServletEventHandlerImpl.processEvent(Unknown Source) at com.Strategy.web.app.beans.ServletEventHandlerImpl.processRequest(Unknown Source) at com.Strategy.web.beans.GenericEventHandler.handleRequest(Unknown Source) at com.Strategy.web.app.beans.ServletEventHandlerImpl.handleRequest(Unknown Source) at com.Strategy.web.beans.GenericEventHandler.processMultipleEventsRequestFlatState(Unknown Source) at com.Strategy.web.beans.GenericEventHandler.handleRequest(Unknown Source) at com.Strategy.web.app.beans.ServletEventHandlerImpl.handleRequest(Unknown Source) at com.Strategy.web.beans.AbstractWebComponent.handleRequest(Unknown Source) at com.Strategy.web.controller.GenericWebAppController.processRequest(Unknown Source) </exception> <clientID>::1</clientID> <userName>Administrator</userName> </record>