bug#14780: Regression: C-n doesn't go to next line under simple circumstances

[Eli Zaretskii]

Does the following fix the problem for you?

=== modified file 'src/xdisp.c'
--- src/xdisp.c 2013-07-16 21:35:45 +0000
+++ src/xdisp.c 2013-07-20 08:21:36 +0000
@@ -15592,7 +15592,8 @@ redisplay_window (Lisp_Object window, in
             Move it back to a fully-visible line.  */
          new_vpos = window_box_height (w);
        }
-      else if (w->cursor.vpos >=0)
+      else if (w->cursor.vpos >=0
+              && PT >= BEGV && PT < ZV)
        {
          /* Some people insist on not letting point enter the scroll
             margin, even though this part handles windows that didn't
@@ -15619,7 +15620,16 @@ redisplay_window (Lisp_Object window, in
              if (header_line)
                window_height += CURRENT_HEADER_LINE_HEIGHT (w);
              if (w->cursor.y >= window_height - pixel_margin)
-               new_vpos = window_height - pixel_margin;
+               {
+                 struct text_pos pos;
+
+                 SET_TEXT_POS (pos, PT, PT_BYTE);
+                 start_display (&it, w, pos);
+                 it.current_y = it.vpos = 0;
+                 move_it_to (&it, ZV, -1, -1, -1, MOVE_TO_POS);
+                 if (it.vpos > margin)
+                   new_vpos = window_height - pixel_margin;
+               }
            }
        }