bug#61525: 29.0.60; delete-frame will raise frames in another virtual desktop

[Daniel Martín]

Kai Ma <justksqsf@gmail.com> writes:

> On MacOS, delete-frame can raise a frame in another virtual desktop,
> which will cause switching between desktops.  This is annoying,
> especially for emacsclient users.
>
> To quote frame.c:
>
> #ifdef NS_IMPL_COCOA
>       else
>       /* Under NS, there is no system mechanism for choosing a new
>          window to get focus -- it is left to application code.
>          So the portion of THIS application interfacing with NS
>          needs to know about it.  We call Fraise_frame, but the
>          purpose is really to transfer focus.  */
>       Fraise_frame (frame1);
> #endif
>
> However, this has an undesired side effect: the desktop will be
> switched.
>
> Steps to reproduce:
>
> 1. Run emacs.
> 2. C-x 5 2, and move the new frame to another desktop.
> 3. C-x 5 0.  Now you see the desktop is switched.
>
> This is a known issue for some time [1] and there is a patch that simply
> disables raise_frame [2].  I'm not sure whether this patch is entirely
> correct (and I think not).  But I do think the behavior should be
> improved; at least the undesired desktop switching should be avoided.
>

One downside of removing raise_frame is that, after you press C-x 5 0,
you cannot start typing right away without first focusing on another
Emacs frame manually.  People would consider this a regression from
previous versions and something that doesn't happen on GNU/Linux.

A possibly better approach could be:

Once the "other" frame to select is chosen by the code that is just
above in frame.c, call some Obj-C code that extracts the EmacsView and
makes it the first responder:

EmacsView *view = FRAME_NS_VIEW (frame1);
[self makeFirstResponder:view];

I haven't tested this, but perhaps this makes the other frame receive
focus without switching desktops in a multi-desktop configuration.