Array<Ctrl> a, b;  // two empty arrays, reference to nothing
a.Create<Label>(); // adds a Label to a, a becomes an array with a single reference at underlying data
a.Create<EditField>(); // adds an EditField to a, a is grown by 1 element, as it had a single reference to data, nothing strange happens.
b = a; // now a AND b have both reference to the same underlying array
b.Create<Label>(); // underlying data is copied ....

Array<Ctrl> a;
a.Create<Label>();
a.Create<EditField>();

Array<Ctrl>&b = a;

b.Create<Label>();

Array<Ctrl> MyFunc()
{
  Array<Ctrl> a;
  a.Create<Label>();
  a.Create<EditField>();

  Array<Ctrl>&b = a;

  b.Create<Label>();

  return b;
}

Array<Ctrl> c = MyFunc();