HBOX, VBOX, HRACK, VRACK     - We layout proportional content more to the application       programmer's expectations.
HBOX, VBOX, HRACK, VRACK
    - We layout proportional content more to the application
      programmer's expectations.

    - When composing space, we maximize the max-minor space
      requirement of children now, instead of minimizing. This avoids
      the effect, that something becomes fixed size as soon as a child
      is fixed sized. The behavior now is, that a box pane is fixed
      size only if every child is fixed size too.

    - children are aligned according to their align-x and align-y
      options.

quek/mcclim,informatimago/mcclim,quek/mcclim,informatimago/mcclim