An activate event is sent when a window or application is being activated or deactivated.
Note: Until wxWidgets 3.1.0 activation events could be sent by wxMSW when the window was minimized. This reflected the native MSW behaviour but was often surprising and unexpected, so starting from 3.1.0 such events are not sent any more when the window is in the minimized state.
See: Overview events, wxApp::IsActive (not implemented in wx)
This class is derived (and can use functions) from: wxEvent
wxWidgets docs: wxActivateEvent
Returns true if the application or window is being activated, false otherwise.