Javawebtart application using JNLP with no codebase or codebase as "." should not get launched using "javaws" or from desktop shortcut but that's not the case as of now.
1) Install JRE6u21 and run any of the jnlp application below:
http://sqeweb.sfbay.sun.com/deployment2/jitu/deployment_mustang_exec_ws/deployment/src/javaws/FunctionalTest/FunctionalTest/jnlp/SimpleJNLPTest.jnlp
http://sqeweb.sfbay.sun.com/deployment2/jitu/deployment_mustang_exec_ws/deployment/src/javaws/FunctionalTest/FunctionalTest/jnlp/SimpleJNLPTest1.jnlp
2) Allow to create shortcut
3) Application will get launched. Now try to launch same app from desktop shortcut and application will get laucnhed again

Another problem is that when we do "javaws -unistall" then desktop shortcut icon against the application mentioned above will not get removed

If you are able to reproduce the behavior then bug is reproduced