patch 7.4.2275
Problem:    ":diffoff!" does not remove filler lines.
Solution:   Force a redraw and invalidate the cursor. (closes #1014)
diff --git a/src/diff.c b/src/diff.c
index c29e944..35e29fc 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -1236,10 +1236,14 @@
 							 : wp->w_p_fen_save;
 
 		foldUpdateAll(wp);
-		/* make sure topline is not halfway a fold */
-		changed_window_setting_win(wp);
 #endif
 	    }
+	    /* remove filler lines */
+	    wp->w_topfill = 0;
+
+	    /* make sure topline is not halfway a fold and cursor is
+	     * invalidated */
+	    changed_window_setting_win(wp);
 
 	    /* Note: 'sbo' is not restored, it's a global option. */
 	    diff_buf_adjust(wp);