// although on MSW it works even if the window is still hidden, it doesn't
// work in other ports (notably X11-based ones) and documentation mentions
// that SetCurrent() can only be called for a shown window, so check for it
// although on MSW it works even if the window is still hidden, it doesn't
// work in other ports (notably X11-based ones) and documentation mentions
// that SetCurrent() can only be called for a shown window, so check for it