The output panel collects output from commands issued by the GUI client. When a command begins to run, a time stamped label is added to the output panel and all of the output from that command is added under this label. If you are running multiple commands at the same time (typically on different servers), the output from each command is sent to the corresponding section making it easy to see the results of each.
You increase or decrease the size of the output panel by sliding the separator at the top of the panel up or down. If you want to open or close this panel, use the Output Panel checkbox on the View Menu. When the output panel is closed, the dialog that initiates each command will stay up, the output will be displayed on that dialog until you dismiss it, and you will not be able to review the output from any command after you have closed that dialog. After the output panel is reopened, the GUI will return to its default behavior.