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

[Roland Winkler]

On Tue May 12 2015 martin rudalics wrote:
> Such things happen to me all the time.  That's why I prefer
> `ediff-setup-windows-plain' (and `split-window-horizontally' as
> `ediff-split-window-function').

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

> The problem is that the entity that issues the message is not aware of
> the intrinsics of ediff.

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"