Fix glyph skipping optimization when a tab line is enabled

* src/dispnew.c (update_text_area): Compute vpos of header line
correctly when window has tab line.

diff --git a/src/dispnew.c b/src/dispnew.c
index 0d959047f3a582e23ece740673216df1c542e803..3cfe1b86f6a70913b733b242bb2ec7d839547852 100644 (file)
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -3928,9 +3928,12 @@ update_text_area (struct window *w, struct glyph_row *updated_row, int vpos)
         However, it causes excessive flickering when mouse is moved
         across the mode line.  Luckily, turning it off for the mode
         line doesn't seem to hurt anything. -- cyd.
-         But it is still needed for the header line. -- kfs.  */
+         But it is still needed for the header line. -- kfs.
+         The header line vpos is 1 if a tab line is enabled.  (18th
+         Apr 2022) */
       || (current_row->mouse_face_p
-         && !(current_row->mode_line_p && vpos > 0))
+         && !(current_row->mode_line_p
+              && (vpos > w->current_matrix->tab_line_p)))
       || current_row->x != desired_row->x)
     {
       output_cursor_to (w, vpos, 0, desired_row->y, desired_row->x);