remove/upload application runs old app

If I upload an application, remove it, modify it and upload it, I see the original application. Only if I terminate-instances then run-instances and then upload the modified application do I see the new version.
I am running on a xen cluster (non-cloud). This occurs using the command line tools as well as with the browser upload/remove. I am modifying and testing the java transaction sample.

Is the expected workflow one in which you must terminate/rerun instances prior to testing modifications to applications? Or is it expected that application names always change? Or am I missing something?

Thanks,
--Mike