bug#47969: 28.0.50; Losing minibuffer focus in trying M-x command

[Gregory Heytings]

> > Stefan, any suggestions or comments?
>
> No, the thread looks pretty complete.
>
> I'll just point out that it's OK to revert the change made for Emacs-25, 
> but at one condition: we need to clearly label the `minibufferp` test 
> with a comment pointing to this discussion so that if the problem that 
> commit was intended to fix comes up again, we'll then have more context 
> to make a better decision.

I have one more comment: the code that was removed from 
handle-select-window by commit 3fdd3bb56c:

;; Don't switch if we're currently in the minibuffer.
;; This tries to work around problems where the
;; minibuffer gets unselected unexpectedly, and where
;; you then have to move your mouse all the way down to
;; the minibuffer to select it.
(window-minibuffer-p)

was added by that same commit in xterm.c:

/* Don't switch if we're currently in the minibuffer.
   This tries to work around problems where the
   minibuffer gets unselected unexpectedly, and where
   you then have to move your mouse all the way down to
   the minibuffer to select it.  */
&& !MINI_WINDOW_P (XWINDOW (selected_window))

but, at least for the recipe of this bug, this code movement does not 
produce the expected effect.

Note also that this condition is not present the corresponding code in 
nsterm.m and w32term.c.