Another case of copying from non-enabled glyphs (bug#74274)

* src/dispnew.c (build_frame_matrix_from_leaf_window): If current window
row is not enabled, don't copy from it.

1 files changed, 15 insertions, 4 deletions

diff --git a/src/dispnew.c b/src/dispnew.c
index 1b8b726b7f3..4758aabe967 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -2636,10 +2636,21 @@ build_frame_matrix_from_leaf_window (struct glyph_matrix *frame_matrix, struct w
 
       if (current_row_p)
         {
-          /* Copy window row to frame row.  */
-          memcpy (frame_row->glyphs[TEXT_AREA] + window_matrix->matrix_x,
-                  window_row->glyphs[0],
-                  window_matrix->matrix_w * sizeof (struct glyph));
+          /* If the desired glyphs for this row haven't been built,
+             copy from the corresponding current row, but only if it
+             is enabled, because ottherwise its contents are invalid.  */
+          struct glyph *to = frame_row->glyphs[TEXT_AREA] + window_matrix->matrix_x;
+          struct glyph *from = window_row->glyphs[0];
+          for (int i = 0; i < window_matrix->matrix_w; ++i)
+            {
+              if (window_row->enabled_p)
+                to[i] = from[i];
+              else
+                {
+                  to[i] = space_glyph;
+                  to[i].frame = f;
+                }
+            }
         }
       else
         {