canvas_rect = new ArdourCanvas::Rectangle (_canvas_group);
CANVAS_DEBUG_NAME (canvas_rect, string_compose ("SV canvas rectangle %1", _trackview.name()));
canvas_rect->set (ArdourCanvas::Rect (0, 0, ArdourCanvas::COORD_MAX, tv.current_height ()));
canvas_rect = new ArdourCanvas::Rectangle (_canvas_group);
CANVAS_DEBUG_NAME (canvas_rect, string_compose ("SV canvas rectangle %1", _trackview.name()));
canvas_rect->set (ArdourCanvas::Rect (0, 0, ArdourCanvas::COORD_MAX, tv.current_height ()));