offset callback but adding a dot overwrites Y-offset. */
p += (int) robust_scm2double (dp.dot_->get_property ("staff-position"), 0.0);
dp.pos_ = p;
offset callback but adding a dot overwrites Y-offset. */
p += (int) robust_scm2double (dp.dot_->get_property ("staff-position"), 0.0);
dp.pos_ = p;