An event being sent when the window is shown or hidden. The event is triggered by calls to wxWindow:show/2, and any user action showing a previously hidden window or vice versa (if allowed by the current platform and/or window manager). Notice that the event is not triggered when the application is iconized (minimized) or restored under wxMSW.
This class is derived (and can use functions) from: wxEvent
wxWidgets docs: wxShowEvent