diff --git a/gen-config.py b/gen-config.py
index e2cc725ce..73b46660b 100755
--- a/gen-config.py
+++ b/gen-config.py
@@ -3,12 +3,28 @@
 # License: GPLv3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
 
+import re
 from kitty.conf.generate import write_output
 
 
 def main() -> None:
     from kitty.options.definition import definition
     write_output('kitty', definition)
+    nullable_colors = []
+    for opt in definition.iter_all_options():
+        if callable(opt.parser_func) and opt.parser_func.__name__ in ('to_color_or_none', 'cursor_text_color'):
+            nullable_colors.append(opt.name)
+    with open('kitty/rc/set_colors.py', 'r+') as f:
+        raw = f.read()
+        nraw = re.sub(
+            r'(# NULLABLE_COLORS_START).+?(\s+# NULLABLE_COLORS_END)',
+            r'\1' + '\n    ' + '\n    '.join(map(lambda x: f'{x!r},', sorted(nullable_colors))) + r'\2',
+            raw, flags=re.DOTALL | re.MULTILINE)
+        if nraw != raw:
+            f.seek(0)
+            f.truncate()
+            f.write(nraw)
+
     from kittens.diff.options.definition import definition as kd
     write_output('kittens.diff', kd)
 
diff --git a/kitty/rc/set_colors.py b/kitty/rc/set_colors.py
index 6a7de869b..3ae1c1dda 100644
--- a/kitty/rc/set_colors.py
+++ b/kitty/rc/set_colors.py
@@ -18,8 +18,15 @@ if TYPE_CHECKING:
 
 
 nullable_colors = (
-    'cursor', 'cursor_text_color', 'tab_bar_background', 'tab_bar_margin_color',
-    'selection_foreground', 'selection_background', 'active_border_color'
+    # NULLABLE_COLORS_START
+    'active_border_color',
+    'cursor',
+    'cursor_text_color',
+    'selection_background',
+    'selection_foreground',
+    'tab_bar_background',
+    'tab_bar_margin_color',
+    # NULLABLE_COLORS_END
 )