boost::mem_fn (&VideoContent::set_left_crop),
boost::bind (&VideoPanel::left_crop_changed, this)
);
_left_right_link = new wxToggleButton (this, wxID_ANY, wxT(""), wxDefaultPosition, wxSize(link_width, link_height));
boost::mem_fn (&VideoContent::set_left_crop),
boost::bind (&VideoPanel::left_crop_changed, this)
);
_left_right_link = new wxToggleButton (this, wxID_ANY, wxT(""), wxDefaultPosition, wxSize(link_width, link_height));