void motion (wxMouseEvent &);
void mouse_wheel (wxMouseEvent &);
boost::optional<std::pair<int, int> > mouse_event_to_channels (wxMouseEvent& ev) const;
void motion (wxMouseEvent &);
void mouse_wheel (wxMouseEvent &);
boost::optional<std::pair<int, int> > mouse_event_to_channels (wxMouseEvent& ev) const;