bug#52491: 28.0.90; Regression in window deletion with minibuffer

[martin rudalics]

> I checked that the value is the same in 27 and 28.

Not here.  If with

(setq enable-recursive-minibuffers t)

followed by M-x, TAB, kp-prior and

M-: (window-parameter nil 'quit-restore)

Emacs 27.2.50 gets me

(window window #<window 4 on  *Minibuf-1*> #<buffer *Completions*>)

while Emacs 28.0.90 gets me nil.

> But while comparing
> quit-restore-window in 27 and 28 indeed there are many differences.
>
> In 27, quit-restore-window calls window--delete, and then later does
> `(select-window (nth 2 quit-restore))'.
>
> But in 28, for the dedicated *Completions* window it calls
> window--delete, but doesn't call `(select-window (nth 2 quit-restore))'
> afterwards, that is another `cond' branch.

All these are easily explained by my observation above.  And, with Emacs
27 the *Completions* window is softly dedicated to its buffer here while
with Emacs 28 it is not dedicated to its buffer.  Please recheck.

martin