diff --git a/cura/CuraApplication.py b/cura/CuraApplication.py
index d7e0f1d374..43c11c26f0 100644
--- a/cura/CuraApplication.py
+++ b/cura/CuraApplication.py
@@ -817,7 +817,7 @@ class CuraApplication(QtApplication):
 
         # Compute the center of the objects when their origins are aligned.
         object_centers = [node.getMeshData().getCenterPosition().scale(node.getScale()) for node in group_node.getChildren() if node.getMeshData()]
-        if object_centers:
+        if object_centers and len(object_centers) > 0:
             middle_x = sum([v.x for v in object_centers]) / len(object_centers)
             middle_y = sum([v.y for v in object_centers]) / len(object_centers)
             middle_z = sum([v.z for v in object_centers]) / len(object_centers)
diff --git a/plugins/PerObjectSettingsTool/PerObjectSettingVisibilityHandler.py b/plugins/PerObjectSettingsTool/PerObjectSettingVisibilityHandler.py
index 1396a02b13..6810ab82aa 100644
--- a/plugins/PerObjectSettingsTool/PerObjectSettingVisibilityHandler.py
+++ b/plugins/PerObjectSettingsTool/PerObjectSettingVisibilityHandler.py
@@ -72,9 +72,9 @@ class PerObjectSettingVisibilityHandler(UM.Settings.Models.SettingVisibilityHand
 
                     # Use the found stack number to get the right stack to copy the value from.
                     if stack_nr in ExtruderManager.getInstance().extruderIds:
-                        stack = UM.Settings.ContainerRegistry.getInstance().findContainerStacks(id=ExtruderManager.getInstance().extruderIds[stack_nr])[0]
+                        stack = UM.Settings.ContainerRegistry.getInstance().findContainerStacks(id = ExtruderManager.getInstance().extruderIds[stack_nr])[0]
 
-                    # Use the raw property to set the value (so the intheritance doesn't break)
+                    # Use the raw property to set the value (so the inheritance doesn't break)
                     if stack is not None:
                         new_instance.setProperty("value", stack.getRawProperty(item, "value"))
                     else: