diff --git a/aiidalab_widgets_base/computational_resources.py b/aiidalab_widgets_base/computational_resources.py
index c52a2c6c..6d0e0df0 100644
--- a/aiidalab_widgets_base/computational_resources.py
+++ b/aiidalab_widgets_base/computational_resources.py
@@ -1302,6 +1302,10 @@ def _observe_code_setup(self, _=None):
         for key, value in self.code_setup.items():
             if hasattr(self, key):
                 if key == "default_calc_job_plugin":
+                    if "None" in value:
+                        # HACK to avoid the warning message
+                        # TODO investigate why it's "None"
+                        return
                     try:
                         self.default_calc_job_plugin.value = value
                     except tl.TraitError: