Your screenshot shows you have hidden both FSX and MSFS products.
They don't become hidden depending if they are installed or not (that's another button that shows installed/not installed), they become hidden only if you have clicked on the icon to hide them, and by default both are visible, or if the simulator they run under is not detected.
The feature is there because some users were annoyed to see P3D products (even if they *do* have P3D installed, otherwise they won't show) together with MSFS product, so we added it, and if you click on it to hide a simulator, the setting is saved between sessions.
You don't say which simulator you have installed, but in your screenshot I see MSFS is not detected. If this is true, than it's normal.
You said however you have GSX, so I can assume you should have either FSX or P3D installed so, the only possible reasons why the P3D products are hidden are:
- You clicked on the icon to hide them
- The simulator hasn't been detected for some reason, like its registry key missing/changed or the sim has been moved.