diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index cb58f24..206ead1 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -4577,7 +4577,7 @@
     if (eap->forceit)
 	bigness = curwin->w_height;
 #ifdef FEAT_WINDOWS
-    else if (firstwin != lastwin)
+    else if (!ONE_WINDOW)
 	bigness = curwin->w_height - 3;
 #endif
     else