This version of FunkeySelectorGUI introduces a new switching method, MB Mode! Simply replace MegaByte.exe with FunkeySelectorGUI.exe and now you will be able to use FSGUI without any mods! This works on any version, without any modifications needed. Currently this method only works with UBFunkeys.exe, but the latest OpenFK nightly supports it.
Full Changelog: v3.0.1...v3.1.0