diff --git a/kitty/marks.py b/kitty/marks.py
index 9bac90628..aa6f6d43f 100644
--- a/kitty/marks.py
+++ b/kitty/marks.py
@@ -15,9 +15,9 @@ def null_marker(*a):
 
 def get_output_variables(left_address, right_address, color_address):
     return (
-        cast(c_void_p(left_address, pointer_to_uint)).contents,
-        cast(c_void_p(right_address, pointer_to_uint)).contents,
-        cast(c_void_p(color_address, pointer_to_uint)).contents,
+        cast(c_void_p(left_address), pointer_to_uint).contents,
+        cast(c_void_p(right_address), pointer_to_uint).contents,
+        cast(c_void_p(color_address), pointer_to_uint).contents,
     )
 
 
@@ -33,7 +33,7 @@ def marker_from_regex(expression, color):
         colorv.value = color
         for match in pat.finditer(text):
             left.value = match.start()
-            right.value = match.end()
+            right.value = match.end() - 1
             yield
 
     return marker
diff --git a/kitty_tests/screen.py b/kitty_tests/screen.py
index ec60e5561..34324249d 100644
--- a/kitty_tests/screen.py
+++ b/kitty_tests/screen.py
@@ -4,6 +4,7 @@
 
 from . import BaseTest
 from kitty.fast_data_types import DECAWM, IRM, Cursor, DECCOLM, DECOM
+from kitty.marks import marker_from_regex
 
 
 class TestScreen(BaseTest):
@@ -453,3 +454,9 @@ class TestScreen(BaseTest):
 
         self.ae(as_text(), 'ababababab\nc\n\n')
         self.ae(as_text(True), 'ababababab\nc\n\n')
+
+    def test_user_marking(self):
+        s = self.create_screen()
+        s.draw('abaa')
+        s.add_marker('a', marker_from_regex('a', 3))
+        self.ae(s.marked_cells(), [(0, 0, 3), (2, 0, 3), (3, 0, 3)])