added check for _key_selection_widget

Author: jo-mueller

src/napari_matplotlib/histogram.py

@@ -148,6 +148,10 @@ def on_update_layers(self) -> None:
         """
         Called when the layer selection changes by ``self.update_layers()``.
         """
+        # reset the axis keys
+        if hasattr(self, "_key_selection_widget"):
+            self._key_selection_widget.reset_choices()
+
         # reset the axis keys
         self._x_axis_key = None