_top_crop->add (crop, wxGBPosition (cr, 1));
add_label_to_sizer (crop, _bottom_crop_label, true, wxGBPosition (cr, 2));
_bottom_crop->add (crop, wxGBPosition (cr, 3));
_top_crop->add (crop, wxGBPosition (cr, 1));
add_label_to_sizer (crop, _bottom_crop_label, true, wxGBPosition (cr, 2));
_bottom_crop->add (crop, wxGBPosition (cr, 3));