Recursively set new normal height of child windows of window PARENT.
HORIZONTAL non-nil means set the new normal width of these
windows. WINDOW specifies a child window of PARENT that has been
resized by THIS-DELTA lines (columns).
Optional argument TRAIL either `before' or `after' means set values
only for windows before or after WINDOW. Optional argument
OTHER-DELTA, a number, specifies that this many lines (columns)
have been obtained from (or returned to) an ancestor window of
PARENT in order to resize WINDOW.