code: public Composite nest(Composite c)
      {
          if (nest!=null)
              return nest.nest(c);
          else
          {
              add(c);
              nest=c;
          }
          return this;
      }
docs: Nest a Composite within a Composite.
  The passed Composite is added to this Composite. Adds to
  this composite are actually added to the nested Composite.
  Calls to nest are passed the nested Composite
  @return The Composite to unest on to return to the original
  state.