// set the currently selected page, return the index of the previously
// selected one (or -1 on error)
// NB: this function will _not_ generate wxEVT_NOTEBOOK_PAGE_xxx events
// set the currently selected page, return the index of the previously
// selected one (or -1 on error)
// NB: this function will _not_ generate wxEVT_NOTEBOOK_PAGE_xxx events