An application sends the IMC_SETOPENSTATUS message to an IME window to open or close the current IME.
msg = (UINT) WM_IME_CONTROL;
wParam = (WPARAM) IMC_SETOPENSTATUS;
lParam = (LPARAM) bOpen;
Returns zero if successful, nonzero otherwise.
When processing this message, the IME window changes the current input context.