diff --git a/MDANSE_GUI/Src/MDANSE_GUI/MolecularViewer/MolecularViewer.py b/MDANSE_GUI/Src/MDANSE_GUI/MolecularViewer/MolecularViewer.py
index 7ff10d9ab..d6b192c7f 100644
--- a/MDANSE_GUI/Src/MDANSE_GUI/MolecularViewer/MolecularViewer.py
+++ b/MDANSE_GUI/Src/MDANSE_GUI/MolecularViewer/MolecularViewer.py
@@ -56,10 +56,8 @@ def array_to_3d_imagedata(data: np.ndarray, spacing: Tuple[float]):
     else:
         image.AllocateScalars(vtk.VTK_DOUBLE, 1)
 
-    for i in range(nx):
-        for j in range(ny):
-            for k in range(nz):
-                image.SetScalarComponentFromDouble(i, j, k, 0, data[i, j, k])
+    for (i, j, k), val in np.ndenumerate(data):
+        image.SetScalarComponentFromDouble(i, j, k, 0, val)
 
     return image
 
@@ -262,13 +260,11 @@ def _draw_isosurface(self, index: int, params=None):
         grid_step = radius / fine_sampling
 
         span = upper_limit - lower_limit
-        grid_steps = [int(x) for x in span / grid_step]
-        gdim = (grid_steps[0], grid_steps[1], grid_steps[2])
+        grid_steps = list((span // grid_step).astype(int))
+        gdim = tuple(grid_steps[0:3])
         grid = np.zeros(gdim, dtype=np.int32)
 
-        indices = np.floor((coords - lower_limit.reshape((1, 3))) / grid_step).astype(
-            int
-        )
+        indices = ((coords - lower_limit.reshape((1, 3))) // grid_step).astype(int)
         unique_indices, counts = np.unique(indices, return_counts=True, axis=0)
         grid[tuple(unique_indices.T)] += counts
         self._atomic_trace_histogram = smear_grid(grid, fine_sampling)
diff --git a/MDANSE_GUI/Src/MDANSE_GUI/MolecularViewer/TraceWidget.py b/MDANSE_GUI/Src/MDANSE_GUI/MolecularViewer/TraceWidget.py
index 588820541..7a9d946d5 100644
--- a/MDANSE_GUI/Src/MDANSE_GUI/MolecularViewer/TraceWidget.py
+++ b/MDANSE_GUI/Src/MDANSE_GUI/MolecularViewer/TraceWidget.py
@@ -61,13 +61,13 @@ def validate(self, input_string: str, position: int):
                 else:
                     state = QValidator.State.Invalid
             else:
-                if len(rgb) > 3:
+                if any([x > 255 for x in rgb]):
+                    state = QValidator.State.Invalid
+                elif len(rgb) > 3:
                     state = QValidator.State.Invalid
                 elif len(rgb) == 3:
                     if all([(x >= 0) and (x < 256) for x in rgb]):
                         state = QValidator.State.Acceptable
-                    elif any([x > 255 for x in rgb]):
-                        state = QValidator.State.Invalid
                 else:
                     state = QValidator.State.Intermediate
         return state, input_string, position