fix: disambiguation condition and stale comment

- Only disambiguate labels when all are non-empty and identical,
  preventing spurious suffixes when mixing named and unnamed figures
- Update stale make_subplots comment in test

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: FBumann

tests/test_figures.py

@@ -867,7 +867,7 @@ def test_titles_from_yaxis_label(self) -> None:
 
     def test_titles_fallback_empty(self) -> None:
         grid = subplots(go.Figure(), go.Figure(), cols=2)
-        # make_subplots omits annotations for empty titles
+        # No annotations are created for empty titles
         titles = [ann.text for ann in grid.layout.annotations]
         assert titles == []
 

xarray_plotly/figures.py

@@ -56,9 +56,9 @@ def _ensure_legend_visibility(
     # --- Step 1: label unnamed traces from source y-axis titles -----------
     labels = [_get_yaxis_title(f) for f in source_figs]
 
-    # If all labels are the same, disambiguate
+    # If all labels are non-empty and identical, disambiguate
     unique_labels = {lb for lb in labels if lb}
-    if len(unique_labels) == 1:
+    if len(unique_labels) == 1 and all(lb for lb in labels):
         labels = [f"{labels[0]} ({i + 1})" for i in range(len(labels))]
 
     for label, sl in zip(labels, trace_slices, strict=False):