// only once per instance's lifetime for each requested wxArtID.
virtual wxBitmap CreateBitmap(const wxArtID& WXUNUSED(id),
const wxArtClient& WXUNUSED(client),
// only once per instance's lifetime for each requested wxArtID.
virtual wxBitmap CreateBitmap(const wxArtID& WXUNUSED(id),
const wxArtClient& WXUNUSED(client),