If there is a beam but no stem, slope calculations depend on this
routine to return where the stem end /would/ be.
*/
- if (!beam && !unsmob_stencil (me->get_property ("stencil")))
+ if (calc_beam && !beam && !unsmob_stencil (me->get_property ("stencil")))
return Interval ();
Real y1 = robust_scm2double ((calc_beam