问题不是"assigned to"字段的含义是什么,而是
当状态 state (status) is changed from open to fixed,
应该不应该改"assigned to"。
It is very often, you should change the "assigned to" to the original submitter
or the QA manager, so that they can be notified and confirm the bug is indeed fixed, and proceed to close the bug. Of course, it completly depends on your workflow. By the way, you can configure the workflow to let all this to happen automatically. See http://www.websina.com/cn/