commit https://github.com/vim/vim/commit/2932359000b2f918d5fade79ea4d124d5943cd07 Author: Bram Moolenaar <Bram@vim.org> Date: Sun Jul 24 22:04:11 2016 +0200 patch 7.4.2101 Problem: Looping over windows, buffers and tab pages is inconsistant. Solution: Use FOR_ALL_ macros everywhere. (Yegappan Lakshmanan)

--- a/src/workshop.c
+++ b/src/workshop.c
@@ -1319,7 +1319,7 @@ get_window(
 {
     win_T	*wp = NULL;	/* window filename is in */
 
-    for (wp = firstwin; wp != NULL; wp = W_NEXT(wp))
+    FOR_ALL_WINDOWS(wp)
 	if (buf == wp->w_buffer)
 	    break;
     return wp;