diff --git a/src/aiidalab_qe/common/panel.py b/src/aiidalab_qe/common/panel.py
index 5224efc27..0620c382d 100644
--- a/src/aiidalab_qe/common/panel.py
+++ b/src/aiidalab_qe/common/panel.py
@@ -287,6 +287,10 @@ def _toggle_code(self, code_model: CodeModel):
             code_widget = self.code_widgets[code_model.name]
         if not code_model.is_rendered:
             self._render_code_widget(code_model, code_widget)
+            code_widget.observe(
+                code_widget.update_resources,
+                "value",
+            )
 
     def _render_code_widget(
         self,
@@ -299,7 +303,7 @@ def _render_code_widget(
         )
         ipw.link(
             (code_model, "selected"),
-            (code_widget.code_selection.code_select_dropdown, "value"),
+            (code_widget, "value"),
         )
         ipw.link(
             (code_model, "num_cpus"),
diff --git a/src/aiidalab_qe/common/widgets.py b/src/aiidalab_qe/common/widgets.py
index b42301083..b36f4c6f6 100644
--- a/src/aiidalab_qe/common/widgets.py
+++ b/src/aiidalab_qe/common/widgets.py
@@ -674,8 +674,7 @@ def __init__(self, **kwargs):
         )
         traitlets.link((self.code_selection, "value"), (self, "value"))
 
-    @traitlets.observe("value")
-    def _update_resources(self, change):
+    def update_resources(self, change):
         if change["new"]:
             self.set_resource_defaults(load_code(change["new"]).computer)