In the menu NES --> Emulation Speed:
Selecting "Turbo" turns on turbo and sets a checkmark to the menu item. If you then select another speed item, such as "Slowest Speed", it will say 100% but still be on turbo, and Turbo is still checked. If you then uncheck Turbo, it applies the slowest speed. Slowest Speed and Normal Speed don't ever get check marks.
Oops, that should say "1%", not "100%".
I'm sorry you don't like it, and I agree it's odd, but it's logical and I won't change the behaviour. Slowest speed affects the current target speed. Turbo is independent of all that. I'll reorganize the menu options so it's more clear
https://github.com/TASVideos/fceux/commit/327bb202a21454eff85dc4f3012443abbe5b38ce
Last edit: zeromus 2019-01-06