action item: warning to extensions authors

In fulfillment of my action item, the following text is suggested as
the final paragraph of section 6.3 (editor's copy) of part 1.

<note><p>
Authors of extensibility elements which may manifest as properties of
the <comp>Description</comp> component should be alert to the impact of
imports on their extensions, or their extensions on imports.  It is not
possible, within the component model, to define extensions which have
an effective scope equal to the scope of a containing file.  Extensions
which modify the behavior of the components contained in a description
may therefore unexpectedly modify the behavior of components in
imported descriptions as well, unless proper care is taken.  Users of
such extension elements should also be aware of the potential pitfalls.
</p></note>

Amy!
-- 
Amelia A. Lewis
Senior Architect
TIBCO/Extensibility, Inc.
alewis@tibco.com