Here is martin's changelog: Have 'split-window' optionally resurrect deleted windows * src/window.c (Fwindow_old_buffer): Handle deleted window as argument. (make_parent_window): Remove function. (Fsplit_window_internal): New argument REFER for resurrecting deleted windows. Incorporate functionality of defunct make_parent_window. (Fdelete_window_internal, delete_all_child_windows): Store any deleted window's buffer in the window's old_buffer slot. (window_dead_windows_table): Make it a 'value' type hash table so the sequence number cannot affect its weakness. * lisp/window.el (split-window): New argument REFER. * doc/lispref/windows.texi (Resurrecting Windows): New section. (Splitting Windows): Explain new argument REFER. (Window Hooks): Rewrite description of 'window-old-buffer'. -- Pranshu Sharma