bug#25179: 26.0.50; Dired doesn't preserve window height

[martin rudalics <rudalics@gmx.at>]

 >> 1. Emacs -Q
 >> 2. C-x 2
 >> 3. M-x dired
 >> 4. press 'm' to mark two or more files
 >> 5. press 'D'
 >>     => the window below becomes larger
 >> 6. answer 'no'
 >>     => the window height is not restored
 >>
 >> The problem is not found with dired on Emacs 24.5.
 > Thank you.
 > For deleting 2-3 files Emacs24 and Emacs25 differs; for deleting
 > many files they looks pretty similar:
 >
 > emacs -Q
 > C-x 2
 > ;; Visit a directory with several hundred of files.
 > M-: (dired (expand-file-name "lisp" source-directory))
 > RET
 > t D no RET
 > ;; In both releases the window displaying *scratch* becames very small.

This is bug#25055.  I yet have to understand why the behavior changed
in the transition from 24.5 to 25.

The problem is that when fitting a window to its buffer steals space
from more than one other window, that space should be returned to those
windows when the window is eventually deleted.  Returning space to more
than one window requires binding ‘window-combination-resize’ to t around
the action deleting the window.  Apparently trivial, I have not yet
found a way to do that reliably.

martin