I have found and fixed a bug in the Sugiyama layout. Example of usage:

b := RTMondrian new.
b shape box color: Color red.
b nodes: (1 to: 100).
b edges connectFrom: [ :v | v // 2 ].
b layout sugiyama.
b normalizer 
normalizeSize: #yourself; 
alphaColor: 0.4.
b

Here is a screenshot in Hapao:

:-)

Alexandre