bug#62592: Not creating new Tabs with small window

[martin rudalics]

> Thanks for the suggestion.  Empirically I found that
> '(split-window-horizontally 1)' always fails.
> So the next patch uses '(split-window-horizontally 2)'.

1 is less than 'window-safe-min-width' (the doc-string of 'split-window'
says in this regard that "this function can make a new window as small
as one line or two columns").  And are you sure you want to copy the
'quit-restore' parameter?  As a rule, in Lisp code never use the
-vertically/-horizontally postfixed forms of 'split-window' unless you
want to mock their interactive behavior.

>> For Emacs 30 I'd recommend a new routine say 'clean-window' to make its
>> argument window pristine.  The way you do it now loses all overlays with
>> a window property in the window's buffer.
>
> The purpose of this trick is to change window identity.  So maybe
> a better name would be 'clone-window'?

Funny - here I use that for a window that can shadow an existing window
for redisplay purposes.  If you want the selected window to change
identity, you should say that in a comment.

martin