diff --git a/docs/changelog.rst b/docs/changelog.rst
index 6c0514c7a..fd6c4e0fa 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -211,6 +211,8 @@ Detailed list of changes
 
 - macOS: Add Copy and Paste menu items to the Edit menu in the global menu bar (:iss:`9780`)
 
+- Fix dragging of splits layout borders sometimes moving in the wrong direction (:pull:`9447`)
+
 0.46.2 [2026-03-21]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/kitty/layout/splits.py b/kitty/layout/splits.py
index 3e8283f1b..b3b636455 100644
--- a/kitty/layout/splits.py
+++ b/kitty/layout/splits.py
@@ -498,9 +498,9 @@ class Pair:
             return False
         if self.two == gid:
             return True
-        if not isinstance(self.two, Pair):
-            return False
-        return self.two.is_group_on_second(gid)
+        if isinstance(self.two, Pair):
+            return self.two.pair_for_window(gid) is not None
+        return False
 
     def find_window_in_tree(self, window_id: int) -> 'list[tuple[Pair, bool]] | None':
         # Returns list of (pair, is_in_one) from self down to the pair containing window_id.