updated for version 7.4.312
Problem:    Cannot figure out what argument list is being used for a window.
Solution:   Add the arglistid() function. (Marcin Szamotulski)
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index a7df2c3..04c9a61 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -7211,6 +7211,7 @@
     else
     {
 	curwin->w_alist->al_refcount = 1;
+	curwin->w_alist->id = ++max_alist_id;
 	alist_init(curwin->w_alist);
     }
 }