My UWP project never received SDL_TEXTEDITING notify

http://www.quandianwan.com/Blackjack/

I develop a cross-platform game use SDL 2.0.10
I finish the Android and Win32 version. And now I am port the UWP version.
The UWP version is good, except the East Asian languages text input.

In UWP version, my game never received the SDL_TEXTEDITING notify.
I do the SDL_StartTextInput and SDL_StopTextInput well, because they works on Android and Win32 well, so the logic is well.

I found the SDL_TEXTEDITING never received on Android and Win32 too.
Dose I need call some function to enable the SDL_TEXTEDITING notify?
Do some open or close operate like switch?

When I input some characters with the IME, my game not popup any IME words select bar window.