Your assessment is correct, that once you add a test to certain test list it is disabled and you can't add it again in the same test list. This is by design, because we consider the each test to be a self sustained functional test for specific scenario. That said, I am open to learning more about your intend to use the same test twice and possibly suggest an alternative.
There is actually one workaround for this scenario, that I can think of right now, and what you need to do is:
- create new web test in your project;
- reference the original test "Example" in a Test as Step;
- add the newly created web test to the test list at the necessary position in the list.
I am looking forward to hearing from you and continue our discussion.