Currently, Closed issues can only be re-opened into the New or Open state. There are many issues that get closed without all/complete information being added/updated, such as Assigner, flags, comments, keywords among others. Going from Closed back to In Progress (one of the two usual "last states" before Close) should be allowed. This will also save a little bit of email spam having to curently do this in two steps: Close -> Open Open -> In Progress
Created attachment 167316 [details] Allowed workflow transitions after change
Created attachment 167317 [details] Status transitions requiring comments