_coverage_frames.push_back (cr);
cr->property_x1() = trackview.editor().frame_to_pixel (t - position);
cr->property_y1() = 1;
cr->property_y2() = _height + 1;
cr->property_outline_pixels() = 0;
_coverage_frames.push_back (cr);
cr->property_x1() = trackview.editor().frame_to_pixel (t - position);
cr->property_y1() = 1;
cr->property_y2() = _height + 1;
cr->property_outline_pixels() = 0;