When you click 'GO', the program gets minimized to the System Tray (bottom-right hand corner of the Start Bar).
Hover over the icon to see the details of the shutdown, or left-click it to bring up the status window.
The top-left box shows the current date and time, and the top-right one shows the target date and time. The bottom box shows the remaining time till shutdown in Days, Hours, Minutes and Seconds. You can click the red 'Abort' button on the right-hand side to cancel the shutdown, or close the window to continue.