Issue 506, or something similar, can still occur

[Keith E OHara]

% Something like issue 506 can still be observed.
%
% Relative to the original report for issue 506,
% remove the slur, and add an accent with a
% forced direction. The beam is badly placed.
%
% I did *not* find this during normal use, but
% while testing a workaround for a different bug.
% Small changes avoid the bug.  In this example, either
% move the accent, or put the slur back in.
% Maybe just file this under 506, so we know there
% are limits to that fix?

\version "2.12.3"
% version 2.13.33 gives visibly the same output

\paper { ragged-right = ##t }
\new PianoStaff <<
   \new Staff = rh { s1 }
   \new Staff = lh \relative c {
     \clef bass
     %
     % LilyPond reports 'programming error: Grob direction
     %     requested while calculation in progress.'
     % Inserting
     %  \stemDown
     % removes this error report, but still produces
     % a badly-placed beam, very similar to original 506.
     %
     e16-\markup{a}_> b'
     \change Staff = rh
     g' b
   }
%{%}>>

lilybug_506.png
Description: PNG image