Followup to 2011-10-19T09:48:35Z!eliz@gnu.org.

 src/xdisp.c (try_window_reusing_current_matrix): If a line ends in a display
 vector or the next line starts in a display vector, continue
 redrawing the window even though the character position of
 start_row was reached.

Fixes: debbugs:9771

2 files changed, 14 insertions, 3 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 9abbe450d3d..c6a23a773de 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -2,6 +2,10 @@
 
         * xdisp.c (start_display): If the character at POS is displayed
         via a display vector, reset IT->current.dpvec_index to zero.
+        (try_window_reusing_current_matrix): If a line ends in a display
+        vector or the next line starts in a display vector, continue
+        redrawing the window even though the character position of
+        start_row was reached.
         (Bug#9771, part 2)
 
 2011-10-18  Chong Yidong  <cyd@gnu.org>
diff --git a/src/xdisp.c b/src/xdisp.c
index 50ddd6b08b8..0757feed1d9 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -16078,13 +16078,20 @@ try_window_reusing_current_matrix (struct window *w)
 
               start_vpos = MATRIX_ROW_VPOS (start_row, w->current_matrix);
             }
-          /* If we have reached alignment,
-             we can copy the rest of the rows.  */
-          if (IT_CHARPOS (it) == CHARPOS (start))
+          /* If we have reached alignment, we can copy the rest of the
+             rows.  */
+          if (IT_CHARPOS (it) == CHARPOS (start)
+              /* Don't accept "alignment" inside a display vector,
+                 since start_row could have started in the middle of
+                 that same display vector (thus their character
+                 positions match), and we have no way of telling if
+                 that is the case.  */
+              && it.current.dpvec_index < 0)
             break;
 
           if (display_line (&it))
             last_text_row = it.glyph_row - 1;
+
         }
 
       /* A value of current_y < last_visible_y means that we stopped