Just to let you know that I've actually opened a ticket with the Eclipse foundation on this one. Even though the file extension is XML, if I select to associate with and open it with a JSP editor I should get all of the JSP editor goodness.
The ticket can be found here:
As an aside, I store the files originally in a revision control system and then deploy them to Windchill's directories when I am finished editing them. Until the Eclipse issue is resolved, I've renamed the files that I'm working on any appended a ".jsp" extension. My deployment script takes that off when it deploys. For example:
Is deployed as
A little hacky, I know, but it works well to achieve both goals. I wish Windchill would just use .jsp for their tasks instead of .xml.