Bool wxAddSecondaryEventHandler(wxEventHandler handlerFunc, Bool pre, Bool override, Bool append)
Add a secondary event handler, pre = TRUE iff it should be called before the event is executed. override = TRUE iff the handler is allowed to override all subsequent events by returning TRUE. Returns TRUE if succeeds.
A secondary event handler is an application-defined handler that may intercept normal events, possibly overriding them. A primary event handler provides the normal behaviour for the event.
An event handler takes a pointer to a wxEvent and a boolean flag which is TRUE if the event was externally generated, and returns a boolean which is TRUE if that event was handled.