diff --git a/dokogen/ui.py b/dokogen/ui.py
index 02bc420..5cd676f 100644
--- a/dokogen/ui.py
+++ b/dokogen/ui.py
@@ -801,7 +801,7 @@ class DokoGenApp:
             import json as _json
             _sp = os.path.join(os.path.dirname(__file__), 'dictionaries', 'spheres.json')
             with open(_sp, encoding='utf-8') as _f:
-                self.is_sphere_combo['values'] = _json.load(_f)
+                self.is_sphere_combo['values'] = [''] + _json.load(_f)
         except Exception:
             pass
 
@@ -812,7 +812,7 @@ class DokoGenApp:
         try:
             _ot = os.path.join(os.path.dirname(__file__), 'dictionaries', 'object_types.json')
             with open(_ot, encoding='utf-8') as _f:
-                self.is_object_type_combo['values'] = _json.load(_f)
+                self.is_object_type_combo['values'] = [''] + _json.load(_f)
         except Exception:
             pass
 
@@ -823,7 +823,7 @@ class DokoGenApp:
         try:
             _ar = os.path.join(os.path.dirname(__file__), 'dictionaries', 'architectures.json')
             with open(_ar, encoding='utf-8') as _f:
-                self.is_architecture_combo['values'] = _json.load(_f)
+                self.is_architecture_combo['values'] = [''] + _json.load(_f)
         except Exception:
             pass
 
@@ -834,7 +834,7 @@ class DokoGenApp:
         try:
             _to = os.path.join(os.path.dirname(__file__), 'dictionaries', 'typical_objects.json')
             with open(_to, encoding='utf-8') as _f:
-                self.is_typical_object_combo['values'] = _json.load(_f)
+                self.is_typical_object_combo['values'] = [''] + _json.load(_f)
         except Exception:
             pass
 
@@ -881,7 +881,7 @@ class DokoGenApp:
             import json as _json
             _nc = os.path.join(os.path.dirname(__file__), 'dictionaries', 'net_categories.json')
             with open(_nc, encoding='utf-8') as _f:
-                self.is_net_category_combo['values'] = _json.load(_f)
+                self.is_net_category_combo['values'] = [''] + _json.load(_f)
         except Exception:
             pass
 
@@ -897,7 +897,7 @@ class DokoGenApp:
         try:
             _np = os.path.join(os.path.dirname(__file__), 'dictionaries', 'net_purposes.json')
             with open(_np, encoding='utf-8') as _f:
-                self.is_net_purpose_combo['values'] = _json.load(_f)
+                self.is_net_purpose_combo['values'] = [''] + _json.load(_f)
         except Exception:
             pass
 
@@ -908,7 +908,7 @@ class DokoGenApp:
         try:
             _nm = os.path.join(os.path.dirname(__file__), 'dictionaries', 'net_methods.json')
             with open(_nm, encoding='utf-8') as _f:
-                self.is_net_method_combo['values'] = _json.load(_f)
+                self.is_net_method_combo['values'] = [''] + _json.load(_f)
         except Exception:
             pass