This method is implemented to perform any initialization before the software-based input panel window is displayed.
This method is called by the software-based input panel when the user toggles the visible status of the software-based input panel on. Programmatically, this occurs when the SIPF_ON flag is toggled in the SIPINFO structure. Use this method to initialize any parameters, structures, and functions that relate to displaying the IM. The IM can also use any data that was stored with a previous call to IInputMethod::Hiding to initialize the window. After this method is complete and the software-based input panel window is shown, the window and its children, such as those created by the IM, receive WM_PAINT messages.