3823587 - Why am I seeing Requests with $0 remaining balance as available to be added to an expense report? 

When attaching a request to an expense report I am able to see Approved and Cancelled requests that have been already attached to the expense report that have $0 remaining balance or even a negative ammount. 
How can I stop these from being shown?

How to make Approved and Cancelled requests already attached to the expense report, with $0 remaining amount not available to be assigned to an expense report? , KBA , CON-CA-ADM-PAS , Policy Assistance , Problem