By calling this method, the Hosting System is asking the Hosted Application to take whatever steps are needed to make its GUI visible as the topmost window, and to gain focus.
If possible, the Hosted Application shall resize and reposition itself to the requestedScreenArea. If requestedScreenArea is missing or null, the Hosted Application may retain its current size and location on the screen.
The method returns TRUE if the Hosted Application received the request and will act on it. Otherwise it returns FALSE.
A Hosted Application shall act on this method if the Hosted Application is in the IDLE or INPROGRESS state. A Hosted Application is not required to act on this method if the Hosted Application is not in the IDLE or INPROGRESS state.
A Hosted Application that has no GUI (e.g. a headless analysis application), where becoming visible and gaining focus has no meaning, shall always return TRUE from this method.