4 May
2023
4 May
'23
1:37 p.m.
From additional tests it looks that like the composition string is simply not updating the edit control selection or text until it is committed.
This is probably because you're testing Japanese or Chinese IMEs. In this case, the composition string is handled in the ime_ui_window_proc.
Because the MS native ime_ui_window_proc is currently implemented more complexly than Wine's, it looks as if the edit control is drawing. However, upon further investigation, this is not the case.