(new vertical-alignment% [parent parent] 
  [[show? show?] 
  [after after]]) 
  (is-a?/c vertical-alignment%)
  parent : (is-a?/c alignment-parent<%>)
  show? : boolean? = #t
  after : (or/c (is-a?/c alignment<%>) false/c) = #f
Inserts a new vertical-alignment container into parent – optionally after a given container also in parent. The new container can be initially shown or hidden.