===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/tmux/grid.c,v
retrieving revision 1.66
retrieving revision 1.67
diff -c -r1.66 -r1.67
*** src/usr.bin/tmux/grid.c	2017/02/22 09:01:32	1.66
--- src/usr.bin/tmux/grid.c	2017/03/07 13:47:56	1.67
***************
*** 1,4 ****
! /* $OpenBSD: grid.c,v 1.66 2017/02/22 09:01:32 nicm Exp $ */
  
  /*
   * Copyright (c) 2008 Nicholas Marriott <nicholas.marriott@gmail.com>
--- 1,4 ----
! /* $OpenBSD: grid.c,v 1.67 2017/03/07 13:47:56 nicm Exp $ */
  
  /*
   * Copyright (c) 2008 Nicholas Marriott <nicholas.marriott@gmail.com>
***************
*** 553,558 ****
--- 553,560 ----
  	grid_expand_line(gd, py, dx + nx, 8);
  	memmove(&gl->celldata[dx], &gl->celldata[px],
  	    nx * sizeof *gl->celldata);
+ 	if (dx + nx > gl->cellused)
+ 		gl->cellused = dx + nx;
  
  	/* Wipe any cells that have been moved. */
  	for (xx = px; xx < px + nx; xx++) {