JUnitLoop doesn't run any tests

[willhains]

I'm still trying to pin this one down, but it is repeatable in my environment:

I have a workspace with many interrelated projects.

1. I turn off "Run in loop" on the JUnit view, and delete the JUnitLoop project (also deleting it from disk).

2. I do a clean and rebuild of the entire workspace.

3. I turn on "Run in loop" on the JUnit view.
   Effect: The JUnitLoop project is recreated with nothing in it.

4. I open a JUnit test case and change something, then save.
   Effect: The log says

   !ENTRY de.devboost.eclipse.jloop 1 0 2014-01-23 07:33:00.752
   !MESSAGE Searching related tests for 1 resource(s).

   And I can see the test I saved in the JUnitLoop project's tests_to_run file, and in the SuiteClasses annotation on LoopTestSuite.
   But no tests are run. I can't see any errors in the log or in the console.
   If I run the LoopTestSuite manually, it works (and the test I saved passes).

This is repeatable in my workspace. But if I create a new workspace to test this out, I cannot reproduce this behaviour. JUnitLoop works perfectly, even if I have multiple projects in the test workspace.