diff --git a/FlatCAMObj.py b/FlatCAMObj.py
index 610df50d..a28e2c73 100644
--- a/FlatCAMObj.py
+++ b/FlatCAMObj.py
@@ -4658,9 +4658,9 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
 
                 try:
                     # set the form with data from the newly selected tool
-                    for tooluid_key, tooluid_value in self.tools.items():
+                    for tooluid_key, tooluid_value in list(self.tools.items()):
                         if int(tooluid_key) == tooluid:
-                            for key, value in tooluid_value.items():
+                            for key, value in list(tooluid_value.items()):
                                 if key == 'data':
                                     form_value_storage = tooluid_value['data']
                                     self.update_form(form_value_storage)
diff --git a/README.md b/README.md
index f02c95aa..65d35d41 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@ CAD program, and create G-Code for Isolation routing.
 
 - modified the new database to accept data from NCC and Paint Tools
 - fixed issues in the new database when adding the tool in a Geometry object
+- fixed a bug in Geometry object that generated a change of dictionary while iterating over it
 
 28.03.2020