Cannot restart WEBrick without deleting a server.pid file manually

I cannot stop/start WEBrick without deleting a server.pid file manually.

If I stop the server in any of usual ways then:
When I try to run I get this message.
A server is already running. Check C:/active/deon/jb/deonJr/tmp/pids/server.pid.
and the server does not start.
If I manually delete that file, the server starts normally.

This is a bit of a nuisance.

Question: am I missing something or is this a bug I should report?

Build 124.305 : (also happened with Rubymine 4.5.4); Rails 3.2.10;  Jruby.

Thanks,
Gordon