Bug fix in the q-section reset.

The problem was that the default value of a tl.List(tl.Float())
is tl.Undefined. Now we explicitely reset the default value
of Q0_vec, h_vec and k_vec

src/aiidalab_qe_vibroscopy/app/widgets/euphonicmodel.py

@@ -105,6 +105,10 @@ def set_model_state(self, parameters: dict):
             setattr(self, k, v)
 
     def _get_default(self, trait):
+        if trait in ["h_vec", "k_vec"]:
+            return [1, 1, 1, 100, 1]
+        elif trait == "Q0_vec":
+            return [0.0, 0.0, 0.0]
         return self.traits()[trait].default_value
 
     def get_model_state(self):

src/aiidalab_qe_vibroscopy/app/widgets/euphonicwidget.py

@@ -118,7 +118,9 @@ class EuphonicSuperWidget(ipw.VBox):
     In between, we trigger the initialization of plots via a button.
     """
 
-    def __init__(self, mode="aiidalab-qe app plugin", model=None, fc=None, q_path=None):
+    def __init__(
+        self, mode="aiidalab-qe app plugin", model=None, node=None, fc=None, q_path=None
+    ):
         """
         Initialize the Euphonic utility class.
         Parameters:
@@ -148,6 +150,7 @@ def __init__(self, mode="aiidalab-qe app plugin", model=None, fc=None, q_path=No
 
         self.mode = mode
         self._model = model  # this is the single crystal model.
+        self._model.node = node
         self._model.fc_hdf5_content = None
 
         self.rendered = False