Variable: even-window-heights
even-window-heights is an alias and customizable for
even-window-sizes, defined in window.el.gz.
Value
t
Documentation
If non-nil display-buffer will try to even window sizes.
Otherwise display-buffer will leave the window configuration
alone. Special values are height-only to even heights only and
width-only to even widths only. Any other value means to even
any of them.
Probably introduced at or before Emacs version 21.1.