diff --git a/openflexure_microscope/api/utilities/gui.py b/openflexure_microscope/api/utilities/gui.py
index dcdfe79e..f55611b4 100644
--- a/openflexure_microscope/api/utilities/gui.py
+++ b/openflexure_microscope/api/utilities/gui.py
@@ -13,6 +13,10 @@ def build_gui_from_dict(gui_description, extension_object):
     # Make a working copy of GUI description
     api_gui = copy.deepcopy(gui_description)
 
+    print("")
+    print(extension_object)
+    print(extension_object._rules)
+
     # Expand shorthand routes into full relative URLs
     if "forms" in gui_description and isinstance(api_gui["forms"], list):
         for form in api_gui["forms"]:
@@ -21,7 +25,7 @@ def build_gui_from_dict(gui_description, extension_object):
                 form["route"] = clean_rule(form["route"])
             # Match rule in extension object
             if "route" in form and form["route"] in extension_object._rules.keys():
-                form["route"] = extension_object._rules[form["route"]]["rule"]
+                form["route"] = extension_object._rules[form["route"]]["urls"][0]
             else:
                 logging.warn(
                     "No valid expandable route found for {}".format(form["route"])