bug#23093: 25.0.92; Change for the worse: minibuffer completion window splits below rather that right

[martin rudalics]

> Before adding a new defcustom variable, could we try to make the
> behavior more DWIM and automatically detect a window configuration
> where displaying *Completions* side-by-side makes more sense like
> in frames with 48-characters height and 2*80-characters width.

IIUC the current scheme pretty well handles the case where multiple
windows are already present when completion is attempted.  And IIRC we
also wanted the *Completions* window appear near the echo area.  Doing
both of these for side-by-side windows seems pretty contrived.  I think
that describing an alternative ‘display-buffer-alist’ spec in the manual
should be sufficient.

> Is it possible to tune ‘temp-buffer-max-height’ to handle this?

‘temp-buffer-max-height’ is effective only if ‘temp-buffer-resize-mode’
is enabled.  ‘temp-buffer-resize-mode’ is not enabled by default.

> Or maybe we need to add new conditional actions like
> ‘display-buffer-below-selected-if-high-enough’ or
> ‘display-buffer-in-right-window-if-height-is-narrow’ or?

Rather not.  In some sense we do the former already although IIUC we
never consult the number of completions before splitting off the window.
The latter looks like a special form of ‘split-window-sensibly’ with all
its problems.

martin