Avoid leaving traces of cursor when entering linum-mode.

 src/fringe.c (draw_fringe_bitmap_1): Don't reduce the width of the
 left fringe if the window has a left margin.  This avoids leaving
 traces of the cursor because its leftmost pixel is not drawn over.

2 files changed, 12 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index e336e3dfe89..2537cd77fdc 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,9 @@
 2012-09-09  Eli Zaretskii  <eliz@gnu.org>
 
+        * fringe.c (draw_fringe_bitmap_1): Don't reduce the width of the
+        left fringe if the window has a left margin.  This avoids leaving
+        traces of the cursor because its leftmost pixel is not drawn over.
+
         * dispnew.c (update_window_line): When the left margin area of a
         screen line is updated, set the redraw_fringe_bitmaps_p flag of
         that screen line.  (Bug#12277)
diff --git a/src/fringe.c b/src/fringe.c
index 97d03a2bfae..0c2109a0f8e 100644
--- a/src/fringe.c
+++ b/src/fringe.c
@@ -659,7 +659,14 @@ draw_fringe_bitmap_1 (struct window *w, struct glyph_row *row, int left_p, int o
         {
           /* If W has a vertical border to its left, don't draw over it.  */
           wd -= ((!WINDOW_LEFTMOST_P (w)
-                  && !WINDOW_HAS_VERTICAL_SCROLL_BAR (w))
+                  && !WINDOW_HAS_VERTICAL_SCROLL_BAR (w)
+                  /* But don't reduce the fringe width if the window
+                     has a left margin, because that means we are not
+                     in danger of drawing over the vertical border,
+                     and OTOH leaving out that one pixel leaves behind
+                     traces of the cursor, if it was in column zero
+                     before drawing non-empty margin area.  */
+                  && NILP (w->left_margin_cols))
                  ? 1 : 0);
           p.bx = x - wd;
           p.nx = wd;