(IT_update_begin): Don't dereference members of struct

window for deleted windows.

2 files changed, 19 insertions, 5 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 413db7655c1..9c4ce9ec50b 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+1999-12-30  Eli Zaretskii  <eliz@is.elta.co.il>
+
+        * msdos.c (IT_update_begin): Don't dereference members of struct
+        window for deleted windows.
+
 1999-12-30  Gerd Moellmann  <gerd@gnu.org>
 
         * abbrev.c (Fexpand_abbrev): If expanding an abbrev which has only
diff --git a/src/msdos.c b/src/msdos.c
index cd969127fe1..3cd0d7e5a4e 100644
--- a/src/msdos.c
+++ b/src/msdos.c
@@ -1711,16 +1711,25 @@ IT_update_begin (struct frame *f)
          Likewise, don't do anything if the frame is garbaged;
          in that case, the frame's current matrix that we would use
          is all wrong, and we will redisplay that line anyway.  */
-      if (!NILP (display_info->mouse_face_window))
+      if (!NILP (display_info->mouse_face_window)
+          && WINDOWP (display_info->mouse_face_window))
         {
           struct window *w = XWINDOW (display_info->mouse_face_window);
           int i;
 
-          for (i = 0; i < w->desired_matrix->nrows; ++i)
-            if (MATRIX_ROW_ENABLED_P (w->desired_matrix, i))
-              break;
+          /* If the mouse highlight is in the window that was deleted
+             (e.g., if it was popped by completion), clear highlight
+             unconditionally.  */
+          if (NILP (w->buffer))
+            display_info->mouse_face_window = Qnil;
+          else
+            {
+              for (i = 0; i < w->desired_matrix->nrows; ++i)
+                if (MATRIX_ROW_ENABLED_P (w->desired_matrix, i))
+                  break;
+            }
 
-          if (i < w->desired_matrix->nrows)
+          if (NILP (w->buffer) || i < w->desired_matrix->nrows)
             clear_mouse_face (display_info);
         }
     }