; * src/dispnew.c (prepare_desired_root_row): Add commentary (bug#74274).

1 files changed, 2 insertions, 0 deletions

diff --git a/src/dispnew.c b/src/dispnew.c
index 260e7ef2d1d..1b8b726b7f3 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -3517,6 +3517,8 @@ prepare_desired_root_row (struct frame *root, int y)
   /* Start with the root's desired matrix row.  If that hasn't been
      redisplayed, copy from the root's current matrix.  */
   struct glyph_row *root_row = MATRIX_ROW (root->desired_matrix, y);
+  /* Don't copy rows that aren't enabled, in particuler because they
+     might not have the 'frame' member of glyphs set.  */
   if (!root_row->enabled_p)
     {
       struct glyph_row *from = MATRIX_ROW (root->current_matrix, y);