Can't reproduce HP-28 operations as objects example

[Orome]

The HP-28 Programming Insights book, in section 3.2.1. gives the example

1 2 {+} LIST→ DROP

to illustrate how operations are treated as objects, stating that placing the + in {..} ensures that it will be placed on the stack rather than being executed when [ENTER] is pressed, and resulting in

1
2
+

on the stack. However if I try to reproduce this I only get as far as

1 2 {+

which results in

1
{2}

on the stack.

What's going on here. Why can't I reproduce the example in the book?