WM_IME_SELECT

The WM_IME_SELECT message will be sent to the UI window when the system is about to change the current IME.

There is no return value.

wParam

TRUE if the IME is newly selected; FALSE if the IME is not selected.

lParam

Handle of the keyboard layout for the IME.

The system IME class uses this message to create a new UI window and to destroy an old UI window for the application or the system. DefWindowProc responds to this message by passing information to the default IME window, which sends the message to its UI window.