bug#41338: Toolbar-bug in Emacs 27.0.91/Pretest

[Stephen Berman]

On Sat, 16 May 2020 22:43:25 +0200 Konrad Podczeck 
<konrad.podczeck@univie.ac.at> wrote:

> To reproduce:
>
> (1) Start Emacs (without any customizations).
>
> (2) Open a file which has the standard toolbar, say mouse.el
>
> (3) Do C-x m, to open a message buffer; this buffer has a toolbar _different_
> from the standard one.
>
> (4) Do C-x 5 2, to get the message buffer shown in a second frame.
>
> (5) In the first frame, make the buffer showing mouse.el active again.
>
> (6) In that buffer, do C-s, to invoke isearch and search for some word.
>
> (7) Using the mouse, close the frame showing mouse.el, but do so in a state
> where still isearch overlays show up.
>
> (8) Now click with mouse-1 in the remaining frame, i.e., in that showing the
> message buffer, and the toolbar changes to the standard one.
>
> I consider this as a bug. In case it is not platform independent, I us an 
> NS-build.

I see this too, on GNU/Linux (both in 27.0.91 and a recent build from
master).  Moreover, if in the remaining frame I switch from the message
buffer to the buffer in which isearch was invoked, the tool bar is now
the isearch tool bar and the mode line has the "Isearch" lighter, but
there are no isearch overlays and point is where it was before invoking
isearch.  This seems surprising.  But now typing C-s restores the
isearch state the buffer had (i.e. the same overlays) before closing the
other frame.

Steve Berman