On Fri, 12 Aug 2022, Eli Zaretskii wrote:

>>
>> Expected result has one window with one line of text in two columns.
>
> Which part of the 2C mode documentation led you to expect to see just
> one window after "F2 1"?
>

The documentation says the following.

```

      When you have edited both buffers as you wish, merge them with ‘<F2>
   1’ or ‘C-x 6 1’ (‘2C-merge’).  This copies the text from the right-hand
   buffer as a second column in the other buffer.  To go back to two-column
   editing, use ‘<F2> s’.

```

Documentation  and  actual behavior  drift  apart  is a  common  place
expectation in  software.  My familiarity  with C-x 1 carried  over to
C-x 6 1.

-- 
vl
 				 ALPINE 2.24 GNU Emacs 27.2 NetBSD 9.3