Make sure to initialize glyph::frame to NULL (bug#77039)

* src/dispnew.c (adjust_glyph_matrix): Clear glyph memory when
enlarging window-system window glyph matrices.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/dispnew.c b/src/dispnew.c
index 4f4dcdf1dfb..683c6ba4226 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -506,8 +506,9 @@ adjust_glyph_matrix (struct window *w, struct glyph_matrix *matrix, int x, int y
               row->glyphs[LEFT_MARGIN_AREA]
                 = xnrealloc (row->glyphs[LEFT_MARGIN_AREA],
                              dim.width, sizeof (struct glyph));
+              memset (row->glyphs[LEFT_MARGIN_AREA], 0,
+                      dim.width * sizeof (struct glyph));
 
-              /* The mode line, if displayed, never has marginal areas.  */
               if ((row == matrix->rows + dim.height - 1
                    && !(w && window_wants_mode_line (w)))
                   || (row == matrix->rows && matrix->tab_line_p)