diff --git a/mne_pipeline_hd/gui/parameter_widgets.py b/mne_pipeline_hd/gui/parameter_widgets.py
index 3d7ca4f..6423b51 100644
--- a/mne_pipeline_hd/gui/parameter_widgets.py
+++ b/mne_pipeline_hd/gui/parameter_widgets.py
@@ -618,10 +618,11 @@ def set_value(self, value):
         # Signal valueChanged is already emitted after first setValue,
         # which leads to second param_value being 0 without being
         # preserved in self.loaded_value
-        self._external_set = True
-        self.param_widget1.setValue(value[0])
-        self.param_widget2.setValue(value[1])
-        self._external_set = False
+        if len(value) == 2:
+            self._external_set = True
+            self.param_widget1.setValue(value[0])
+            self.param_widget2.setValue(value[1])
+            self._external_set = False
 
     def _get_param(self):
         if not self._external_set:
diff --git a/mne_pipeline_hd/tests/test_parameter_widgets.py b/mne_pipeline_hd/tests/test_parameter_widgets.py
index d9fc029..322c097 100644
--- a/mne_pipeline_hd/tests/test_parameter_widgets.py
+++ b/mne_pipeline_hd/tests/test_parameter_widgets.py
@@ -154,8 +154,7 @@ def test_basic_param_guis(qtbot, gui_name):
             }
             kwargs["type_kwargs"][type_gui_name] = t_kwargs
         gui = gui_class(data=parameters, name=gui_name, **kwargs)
-        for gui_type, type_gui_name in gui.gui_types.items():
-            type_idx = gui.types.index(gui_type)
+        for type_idx, (gui_type, type_gui_name) in enumerate(gui.gui_types.items()):
             gui.change_type(type_idx)
             gui.set_param(parameters[type_gui_name])
             assert gui.get_value() == parameters[type_gui_name]