Check that category was selected before fetching templates

InvenTree/part/forms.py

@@ -215,6 +215,7 @@ class EditPartForm(HelperForm):
     class Meta:
         model = Part
         fields = [
+            'confirm_creation',
             'category',
             'selected_category_templates',
             'parent_category_templates',
@@ -224,7 +225,6 @@ class EditPartForm(HelperForm):
             'revision',
             'bom_copy',
             'parameters_copy',
-            'confirm_creation',
             'keywords',
             'variant_of',
             'link',

InvenTree/part/models.py

@@ -350,7 +350,7 @@ class Part(MPTTModel):
             # Get part category
             category = self.category
 
-            if add_category_templates:
+            if category and add_category_templates:
                 # Store templates added to part
                 template_list = []