GP only allows one report or document to be printed to screen at a time. If you try printing a second document before the first has completed and the screen has been closed, you won't be able to view the second or subsequent reports. You must close all previous screen prints before the most recent one will appear.
On a related note, if you're printing a report that takes a long time to process, and you're wondering if you actually hit the print button, you can see if the report is in the Process queue and view the progress of the report using the Process Monitor.
File>Process Monitor
* click image to enlarge
All processes that are currently being run in GP will appear in the 'Process' window. Any process preceded by a '>' (greater than) sign can be removed (canceled).
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