Daniel Martín via "Bug reports for GNU Emacs, the Swiss army knife of
text editors" <bug-gnu-emacs@gnu.org> writes:

>
> 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.

The attached patch avoids the unwanted side effects of raise-frame by
making the other frame the key window, instead.  Could you give it a
try?