diff --git a/src/aiidalab_qe_vibroscopy/app/settings.py b/src/aiidalab_qe_vibroscopy/app/settings.py
index b400fe7..be88215 100644
--- a/src/aiidalab_qe_vibroscopy/app/settings.py
+++ b/src/aiidalab_qe_vibroscopy/app/settings.py
@@ -14,14 +14,49 @@
 from aiidalab_qe.common.panel import Panel
 from IPython.display import clear_output, display
 
+
 import sys
 import os
+
+from aiida.plugins import CalculationFactory, DataFactory, WorkflowFactory
+
+HubbardStructureData = DataFactory("quantumespresso.hubbard_structure")
+
+# spinner for waiting time (supercell estimations)
+spinner_html = """
+<style>
+@keyframes spin {
+  0% { transform: rotate(0deg); }
+  100% { transform: rotate(360deg); }
+}
+
+.spinner {
+  display: inline-block;
+  width: 15px;
+  height: 15px;
+}
+
+.spinner div {
+  width: 100%;
+  height: 100%;
+  border: 4px solid #f3f3f3;
+  border-top: 4px solid #3498db;
+  border-radius: 50%;
+  animation: spin 1s linear infinite;
+}
+</style>
+<div class="spinner">
+  <div></div>
+</div>
+"""
+
+
 def disable_print(func):
     def wrapper(*args, **kwargs):
         # Save the current standard output
         original_stdout = sys.stdout
         # Redirect standard output to os.devnull
-        sys.stdout = open(os.devnull, 'w')
+        sys.stdout = open(os.devnull, "w")
         try:
             # Call the function
             result = func(*args, **kwargs)
@@ -30,6 +65,7 @@ def wrapper(*args, **kwargs):
             sys.stdout.close()
             sys.stdout = original_stdout
         return result
+
     return wrapper
 
 
@@ -149,7 +185,7 @@ def change_supercell(_=None):
         )
         # supercell hint (15A lattice params)
         self.supercell_hint_button.on_click(self._suggest_supercell)
-        
+
         # reset supercell
         self.supercell_reset_button = ipw.Button(
             description="Reset",
@@ -159,13 +195,13 @@ def change_supercell(_=None):
         )
         # supercell reset reaction
         self.supercell_reset_button.on_click(self._reset_supercell)
-        
+
         # Estimate the number of supercells for frozen phonons.
         self.supercell_number_estimator = ipw.HTML(
-                    description="Number of supercells to be computed:",
-                    value = "0",
-                    style={"description_width": "initial"},
-                )
+            description="Number of supercells to be computed:",
+            value="0",
+            style={"description_width": "initial"},
+        )
 
         ## end supercell hint.
 
@@ -174,11 +210,11 @@ def change_supercell(_=None):
                 self.hint_button_help,
                 ipw.HBox(
                     [
-                        self.supercell_selector, 
-                        self.supercell_hint_button, 
+                        self.supercell_selector,
+                        self.supercell_hint_button,
                         self.supercell_number_estimator,
                         self.supercell_reset_button,
-                        ],
+                    ],
                 ),
             ]
         )
@@ -213,6 +249,11 @@ def change_supercell(_=None):
 
         super().__init__(**kwargs)
 
+        # we define a block for the estimation of the supercell if we ask for hint,
+        # so that we call the estimator at the end (we don't lose time).
+        # see the methods below.
+        self.block = False
+
     @tl.observe("input_structure")
     def _update_input_structure(self, change):
         if self.input_structure is not None:
@@ -238,13 +279,18 @@ def _suggest_supercell(self, _=None):
             suggested_3D = 15 // np.array(s.cell.cellpar()[:3]) + 1
 
             # if disabled, it means that it is a non-periodic direction.
+            # here we manually unobserve the `_estimate_supercells`, so it is faster
+            # and only compute when all the three directions are updated
+            self.block = True
             for direction, suggested, original in zip(
                 [self._sc_x, self._sc_y, self._sc_z], suggested_3D, s.cell.cellpar()[:3]
             ):
                 direction.value = suggested if not direction.disabled else 1
+            self.block = False
+            self._estimate_supercells()
         else:
             return
-    
+
     @tl.observe("input_structure")
     @disable_print
     def _estimate_supercells(self, _=None):
@@ -252,28 +298,66 @@ def _estimate_supercells(self, _=None):
 
         Estimate the number of supercells to be computed for frozen phonon calculation.
         """
+        if self.block:
+            return
+
+        self.supercell_number_estimator.value = spinner_html
+
         from aiida_phonopy.data.preprocess import PreProcessData
-        
-        supercells = PreProcessData(
-                    structure=self.input_structure,
-                    supercell_matrix=[
-                        [self._sc_x.value, 0, 0], 
-                        [0, self._sc_y.value, 0], 
-                        [0, 0, self._sc_z.value]],
-                    symprec=1e-5,
-                    distinguish_kinds=False,
-                    is_symmetry=True,
-                    ).get_supercells_with_displacements()
-        
-        self.supercell_number_estimator.value = f"{len(supercells)}"
-        
-        return 
+
+        if self.input_structure:
+            preprocess_data = PreProcessData(
+                structure=self.input_structure,
+                supercell_matrix=[
+                    [self._sc_x.value, 0, 0],
+                    [0, self._sc_y.value, 0],
+                    [0, 0, self._sc_z.value],
+                ],
+                symprec=1e-5,
+                distinguish_kinds=False,
+                is_symmetry=True,
+            )
+
+            supercells = preprocess_data.get_supercells_with_displacements()
+
+            # for now, we comment the following part, as the HubbardSD is generated in the submission step.
+            """if isinstance(self.input_structure, HubbardStructureData):
+                from aiida_vibroscopy.calculations.spectra_utils import get_supercells_for_hubbard
+                from aiida_vibroscopy.workflows.phonons.base import get_supercell_hubbard_structure
+                supercell = get_supercell_hubbard_structure(
+                    self.input_structure,
+                    self.input_structure,
+                    metadata={"store_provenance": False},
+                )
+                supercells = get_supercells_for_hubbard(
+                    preprocess_data=preprocess_data,
+                    ref_structure=supercell,
+                    metadata={"store_provenance": False},
+                )
+
+            else:
+                supercells = preprocess_data.get_supercells_with_displacements()
+            """
+            self.supercell_number_estimator.value = f"{len(supercells)}"
+
+        return
 
     def _reset_supercell(self, _=None):
-        for direction in [self._sc_x, self._sc_y, self._sc_z]:
-                direction.value = 2
+        if self.input_structure is not None:
+            reset_supercell = []
+            self.block = True
+            for direction, periodic in zip(
+                [self._sc_x, self._sc_y, self._sc_z], self.input_structure.pbc
+            ):
+                if periodic:
+                    reset_supercell.append(2)
+                else:
+                    reset_supercell.append(1)
+            (self._sc_x.value, self._sc_y.value, self._sc_z.value) = reset_supercell
+            self.block = False
+            self._estimate_supercells()
         return
-    
+
     def get_panel_value(self):
         """Return a dictionary with the input parameters for the plugin."""
         return {