The way the queue works a single job is not supposed to appear more than once, so if you seem to be experiencing that then there’s a bug.
One way to check what’s in the queue is to use the main menu “About” item, then click on the “System info” button, then scroll down to the “Server state properties” section and find the following lines:
activeTask
is the ID of the currently running task (if any)proposedSchedule
is the “not yet in queue, but expected to be put in queue at …” listschedulerQueueIds
is the list of items CURRENTLY in the queue
(Thanks for kenkendk for the above descriptions!)
For a summary of how the scheduler is supposed to run, see here: