I use a setup with several build nodes (about 200 split on 5-15 computers) The matrix job is used to run 100-200 different versions of the build with run time 10-120 minutes.

One category with limits on total jobs was created and two matrix jobs where queued up. The from what I could see the limiting of number of running child jobs worked but the main user interface of jenkins was almost totally blocked from handle external requests in the processes.

Trying the same addon on my test system with fewer executors shorter queue does not lock up the user interface.

Why are you reporting a bug not on latest?

I need the addon to limit the number of sub jobs (As described in JENKINS-16521) this feature is completely broken in 1.7.2 So I tried this with 1.7.1