isearch semantics, 23 vs 24

[Tom Roche]

I recently moved from GNU Emacs 23.3.1 to GNU Emacs 24.0.91.1 (both on
debian). Mostly I'm happy, but a change in behavior of isearch is
annoying me, and I'd appreciate help fixing it in my configuration.

Consider the following (cited) fragment of a log buffer:

> ----------------------------------------------------------------------
> M 10 Oct 11:
>
> build 08:35-12:07
> run 13:45-16:15
> debug 17:00-17:39
> doc, commit 18:50-19:39
>
> ----------------------------------------------------------------------
> T 11 Oct 11:

Put point at the beginning of the (uncited) fragment (i.e., remove the
citing, and put cursor atop the first '-'). In emacs 23 (and for as
long as I can remember before that), if I then did

C-s C-y C-s

I would get a search for the entire first line (of '-'): point would be
at the end of the second separator, which would be found/highlighted--
this I expect, know (certainly my fingers know this :-), and prefer.
But in emacs 24,

C-s C-y C-s

causes a (usually failing) search for whatever was last killed; instead,
to get the desired behavior, I must do

C-s M-s C-e C-s

Is there an easy way to make my init.el (aka .emacs) tell emacs 24
that I want the old semantics for this usecase? Alternatively, how
best/easiest to restore the old behavior?

TIA, Tom Roche <Tom_Roche@pobox.com>