Sync OpenBSD patchset 142:

Each window now has a tree of layout cells associated with it. In this tree,
each node is either a horizontal or vertical cell containing a list of other
cells running from left-to-right or top-to-bottom, or a leaf cell which is
associated with a pane.

The major functional changes are:

- panes may now be split arbitrarily both horizontally (splitw -h, C-b %) and
  vertically (splitw -v, C-b ");
- panes may be resized both horizontally and vertically (resizep -L/-R/-U/-D,
  bound to C-b left/right/up/down and C-b M-left/right/up/down);
- layouts are now applied and then may be modified by resizing or splitting
  panes, rather than being fixed and reapplied when the window is resized or
  panes are added;
- manual-vertical layout is no longer necessary, and active-only layout is gone
  (but may return in future);
- the main-pane layouts now reduce the size of the main pane to fit all panes
  if possible.

Thanks to all who tested.

cmd-break-pane.c

@@ -1,4 +1,4 @@
-/* $Id: cmd-break-pane.c,v 1.4 2009-07-14 06:43:32 nicm Exp $ */
+/* $Id: cmd-break-pane.c,v 1.5 2009-07-20 15:42:05 tcunha Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -74,17 +74,17 @@ cmd_break_pane_exec(struct cmd *self, struct cmd_ctx *ctx)
 		if (wl->window->active == NULL)
 			wl->window->active = TAILQ_NEXT(wp, entry);
 	}
- 	layout_refresh(wl->window, 0);
+ 	layout_close_pane(wp);
 
  	w = wp->window = window_create1(s->sx, s->sy);
  	TAILQ_INSERT_HEAD(&w->panes, wp, entry);
  	w->active = wp;
  	w->name = default_window_name(w);
+	layout_init(w);
 
  	wl = session_attach(s, w, -1, &cause); /* can't fail */
  	if (!(data->chflags & CMD_CHFLAG('d')))
  		session_select(s, wl->idx);
- 	layout_refresh(w, 0);
 
 	server_redraw_session(s);