bug#2282: 23.0.90; rmail -- rmail-summary splits frame into three parts...

[Alfred M. Szmidt]

   > When one does a M-x rmail, and then invokes rmail-summary, the frame
   > is split into three parts:
   > 
   > +-----------+----------+
   > |           |          |
   > | *scratch* |  rmail   |
   > |           |          |
   > +-----------+----------+
   > |   rmail-summary      |
   > |                      |
   > +----------------------+

   Does this happen with "emacs -Q"? cause it never happened to me.

Even with -Q.

   Or perhaps you started Rmail from this window configuration:

    +-----------+----------+
    |                      |
    |      *scratch*       |
    |                      |
    +-----------+----------+
    |        rmail         |
    |                      |
    +----------------------+

   in the first place??

No, initial window configuration looks like this:

    +----------------------+
    |                      |
    |      *scratch*       |
    |                      |
    |                      |
    |                      |
    |                      |
    +----------------------+

But if rmail would split into three frames, based on the window
configuration you mentioned, then I would consider it a bug as well.
Atleast, it was not the behaviour of rmail before the mbox merge.