diff --git a/src/hqt/tmux/runner.py b/src/hqt/tmux/runner.py
index 5311352..b58cb88 100644
--- a/src/hqt/tmux/runner.py
+++ b/src/hqt/tmux/runner.py
@@ -351,8 +351,10 @@ class TmuxRunner:
             return None
         window_id = stdout.strip()
 
-        # Style by window_id: automatic-rename off, the @hqt_label, then the
-        # Frappé per-window theme — one atomic invocation (";" argv separators).
+        # Style by window_id: automatic-rename + allow-rename off (nvim/lazygit
+        # emit OSC title sequences that would otherwise scramble the label), the
+        # @hqt_label, then the Frappé per-window theme — one atomic invocation
+        # (";" argv separators). Mirrors new_window's window-option setup.
         rc, _, err = await self._exec(
             "set-option",
             "-w",
@@ -365,6 +367,13 @@ class TmuxRunner:
             "-w",
             "-t",
             window_id,
+            "allow-rename",
+            "off",
+            ";",
+            "set-option",
+            "-w",
+            "-t",
+            window_id,
             "@hqt_label",
             label,
             ";",
diff --git a/tests/test_tmux.py b/tests/test_tmux.py
index c9047b8..52ffb08 100644
--- a/tests/test_tmux.py
+++ b/tests/test_tmux.py
@@ -1021,7 +1021,7 @@ async def test_new_aux_window_spawns_styles_and_selects(runner):
     runner._exec.side_effect = [
         (0, "0\n", ""),   # _next_window_index: indices [0] -> next index 1
         (0, "@7\n", ""),  # new-window -P -F '#{window_id}'
-        (0, "", ""),      # set-option (automatic-rename + @hqt_label + theme)
+        (0, "", ""),      # set-option (automatic-rename + allow-rename + @hqt_label + theme)
         (0, "", ""),      # select-window
     ]
     wid = await runner.new_aux_window("lazygit", "/proj", ["lazygit"], "lazygit · proj")
@@ -1037,6 +1037,8 @@ async def test_new_aux_window_spawns_styles_and_selects(runner):
     assert calls[2].args[:6] == (
         "set-option", "-w", "-t", "@7", "automatic-rename", "off",
     )
+    # allow-rename off too, so nvim/lazygit OSC titles can't scramble the label.
+    assert "allow-rename" in calls[2].args
     assert "@hqt_label" in calls[2].args
     assert "lazygit · proj" in calls[2].args
     assert "remain-on-exit" not in calls[2].args