Hi there,
I've had this exact same issue, though with different configuration: I'm working off a localhost server and I had another server connected - remote server displaying on top and local server on bottom. For some reason the expand/collapse [+]/[-] buttons were gone for all jobs on the remote server, while the local ones were fine. Both are 5.7.4.
For what it's worth, the buttons showed up again after I disconnected the client from the remote server, and then reconnected.
Regards,