Japanese IME - Text Composition Clause?

After SDL_StartTextInput has been activated and you start typing, is there a way to display the Composition Clause?

I’m using a c# github library that uses SDL for its OpenGL IMEHelper that makes use of the StartTextInput, StopTextInput and SetTextInputRect functions. The default candidate window displays but I’m not getting the text composition displaying like it would on anything else (I’m using Windows 10). I don’t know if this is an issue with the library I’m using or a limitation of SDL.

Is this a limitation of SDL? If not, how do I get the composition to display?

Any help is appreciated.

This is when some characters are grouped in a character in IME input like in notepad, and they are shown as this new thing?

If it’s that, in the codebase where WM_IME_COMPOSITION in Windows I don’t see anything for GCS_COMPCLAUSE, so I think it’s just not implemented.