bug#20538: 24.4; Attempt to delete a surrogate minibuffer frame

[martin rudalics]

> How do you use the undocumented function ediff-setup-windows-plain?
> (Could this usage be properly documented?)

It's an option (a customizable variable).  Do

M-: (require 'ediff) RET

C-h v RET ediff-window-setup-function RET

> Sure.  I was more thinking that quite generally the error message
> talking about a "surrogate minibuffer frame" is a bit confusing if
> one has no clue what this term means.  When I first saw this
> message, I thought of something like a "minibuffer frame" that was
> some kind of surrogate (which was why I thought this was supposed to
> refer to the Ediff control panel that acts like a minibuffer for an
> ediff session).
>
> Perhaps the error message could be changed to something like
>
>    "Attempt to delete frame with a surrogate minibuffer for frame XYZ"

Maybe we should say in the documentation of `delete-frame' something
like

  A frame may not be deleted if its minibuffer serves as surrogate
  minibuffer for another frame.

martin