Tell users the native title bar setting needs a restart

The setting appears to have been removed altogether which is a UX Problem IMO Many desktops do different things with their window buttons and many even offer the option to customize them, including Cinnamon which is used by Linux Mint, and KDE Plasma which is used by many Linux distributions including SteamOS. By forcing Fluxer's custom Window Decorations on the user, you may be forcing them to make an exception to their muscle memory and workflow for one particular app.