From d37a9fd48a6ced9e13578d7a5456412dae77f5f9 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 19 Mar 2026 09:35:56 +0000
Subject: [PATCH] Fix marker highlighting for CJK/wide chars not at position 0

Fixes #9705
Fixes #9706
---
 kitty/line.c          |  2 +-
 kitty_tests/screen.py | 17 ++++++++++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/kitty/line.c b/kitty/line.c
index c81f10a3e..fd2212342 100644
--- a/kitty/line.c
+++ b/kitty/line.c
@@ -984,7 +984,7 @@ apply_mark(Line *line, const uint16_t mark, index_type *cell_pos, unsigned int *
             }
         } else if (line->cpu_cells[x].is_multicell) {
             *match_pos += lc.count - 1;
-            index_type x_limit = MIN(line->xnum, mcd_x_limit(line->cpu_cells + x));
+            index_type x_limit = MIN(line->xnum, x + mcd_x_limit(line->cpu_cells + x));
             for (; x < x_limit; x++) { MARK; }
             x--;
         } else {
diff --git a/kitty_tests/screen.py b/kitty_tests/screen.py
index 556268057..cbd029b8b 100644
--- a/kitty_tests/screen.py
+++ b/kitty_tests/screen.py
@@ -3,7 +3,7 @@
 
 from kitty.config import defaults
 from kitty.fast_data_types import DECAWM, DECCOLM, DECOM, IRM, VT_PARSER_BUFFER_SIZE, Color, ColorProfile, Cursor
-from kitty.marks import marker_from_function, marker_from_regex
+from kitty.marks import marker_from_function, marker_from_regex, marker_from_text
 from kitty.window import pagerhist
 
 from . import BaseTest, draw_multicell, parse_bytes
@@ -999,6 +999,21 @@ class TestScreen(BaseTest):
         s.draw('x')
         s.set_marker(marker_from_function(mark_x))
         self.ae(s.marked_cells(), [(2, 0, 1), (4, 0, 2)])
+        # Test CJK/wide characters not at position 0 (issue #9705)
+        s = self.create_screen(cols=20)
+        s.draw('テスト世界')
+        s.set_marker(marker_from_regex('テ', 3))
+        self.ae(s.marked_cells(), cells(0, 1))
+        s.set_marker(marker_from_regex('世', 3))
+        self.ae(s.marked_cells(), cells(6, 7))
+        s.set_marker(marker_from_text('世界', 3))
+        self.ae(s.marked_cells(), cells(6, 7, 8, 9))
+        s = self.create_screen(cols=20)
+        s.draw('ABテCD世EF')
+        s.set_marker(marker_from_regex('テ', 3))
+        self.ae(s.marked_cells(), cells(2, 3))
+        s.set_marker(marker_from_regex('世', 3))
+        self.ae(s.marked_cells(), cells(6, 7))
 
     def test_hyperlinks(self):
         s = self.create_screen()