Extending root level Application.cfc files

<cfcomponent extends="/.Application">
<cfset this.name="sub_application_name">
... methods ...
... methods ...
</cfcomponent>

That will force ColdFusion to look for the root Application.cfc file and retain your session management.

Since application behavoir starts in the local folder; if you use "Application" without the /. the code will fail saying something about the component cannot extend itself.