patch 8.1.1756: autocommand that splits window messes up window layout commit https://github.com/vim/vim/commit/1417c766f55e5959b31da488417b7d9b141404af Author: Bram Moolenaar <Bram@vim.org> Date: Sat Jul 27 17:31:36 2019 +0200 patch 8.1.1756: autocommand that splits window messes up window layout Problem: Autocommand that splits window messes up window layout. Solution: Disallow splitting a window while closing one. In ":all" give an error when moving a window will not work.

--- a/src/buffer.c
+++ b/src/buffer.c
@@ -5101,6 +5101,13 @@ do_arg_all(
 			    new_curwin = wpnext;
 			    new_curtab = curtab;
 			}
+			else if (wpnext->w_frame->fr_parent
+						 != curwin->w_frame->fr_parent)
+			{
+			    emsg(_("E249: window layout changed unexpectedly"));
+			    i = count;
+			    break;
+			}
 			else
 			    win_move_after(wpnext, curwin);
 			break;