I have 3 computers. One computer works as master (M) the two others (S1, S2) as slave.
Jenkins version is 1.551
OS is Windows7, Server 2003/8
The builds runs only on the slaves.
I have one Job defined. This job runs a batch with individual parameters. Parallel build for the job is enabled. The job uses a custom workspace, e.g. D:\jenkins-ws\${JOB_NAME}\workspace

I noticed the following behavior if I run this job concurrent.
1. I’m on the Jenkins master, and run the job. Job is scheduled on Slave S1.
2. Build is running on S1, in the WebUI I see a Workspace 1 (W1) under Jenkins/<Job>
3. I’m starting the job again (maybe with other parameter), Job is scheduled on Slave 2
4. In the WebUI the workspace W1 disappears and a Workspace W2 for the second job is shown
After finishing of both jobs the workspace directories exist on the corresponding slave machines, but not I the WebUI -> there’s only the second workspace reachable.
e.g. https://<machine>:8080/job/<job>/ws/2
If I try the address https://<machine>:8080/job/<job>/ws/1 then I got an error 404.
If I restart the Jenkins machines the behavior stays: only the workspaces of the latest of identical concurrent jobs are shown.
Why the first job is dropped in the UI? How can I change the behavior so that all workspace of concurrent builds of the same jobs a shown?