Why are my Test Classes (marked @isTest) getting listed with Code Coverage?

It is very simple

 1. Copy the listed test class and paste into notepad.
 2. Delete the listed test class.
 3. Create new test class with **same class name** and **same body**(structure).
 4. Finally Run the test class.

100% it works.Now you test class it not listed with code coverage.

Does this happen both when running tests from the IDE/ant and when running tests in the UI?

There's a bug in the IDE/ant case that I'm working on currently.