You don't say which sim you use.
If you use P3D, the problem doesn't have anything to do with GSX and it's a known bug in versions before to the very latest (3.4.9) that didn't displayed all the menu entries, and some users don't realize that window CAN be resized.
Following our report, this has been fixed in 3.4.9, so there's always a "next" automatically added even if the Simconnect menu window it's too small to contain all items and/or you haven't realized you can resize it with the mouse.