1. add a new test case in TestLink
2. add a new test plan in TestLink
3. add the new created test case to the new created test plan.
4. then, can not retrieve the test case

BTW:
1. the old test plan(3.5) with the old test case(3.5) which i create before TestLink Plugin 3.6 can be retrieved.
2. i add the new created test case(3.6) to the old test plan(3.5), only old test case can be retrieve.
3. My TestLink version is 1.9.7, TestLink Plugin version is 3.6.