Forge: 14.23.5.2847
Simply Jetpacks 2: 2.2.16.1

Some of the config buttons on the ingame config are grayed out and unable to be pressed. This is the case for the Item Settings Category and the Integration Settings Category

You cannot edit these config values while in a loaded world, as a game restart is required. You can edit these from the main menu and then restart the game to apply them.

If this is the case, then why not annotate the config fields with @Config.RequiresMCRestart or @Config.RequiresWorldRestart ? This will allow the values to be changed in game, but will display a warning message when the user exits the Mod Config screen informing them that they need to restart for the changes to occur.