If a time-off request is eligible for auto-granting but there is no appropriate time slot available, the request is "wait listed" until that time becomes available and then it is auto-granted (auto-grant must be enabled).
The wait list functionality puts into a queue agents who request unavailable time off, in the order of when each request was made. If the time slot becomes available, agents in that queue are granted their requests, in order. Ask your supervisor whether or not this process is automatic depends upon the wait list and autogrant settings that are specified by the WFM administrator.
To see how many others are present on a timestep's wait list, click the cursor on that timestep. A date-and-time information box appears, which also displays the label Wait-List followed by the number of people who are currently in the queue for time off in that time step.
In addition, the information box displays the label Time Off Limit and the corresponding number for that time step.