Fix #708
diff --git a/user_guide_src/source/general/common_functions.rst b/user_guide_src/source/general/common_functions.rst
index f3d48ac..7f327f0 100644
--- a/user_guide_src/source/general/common_functions.rst
+++ b/user_guide_src/source/general/common_functions.rst
@@ -46,10 +46,14 @@
config_item('item_key')
=======================
-The :doc:`Config library <../libraries/config>` is the preferred way of
-accessing configuration information, however config_item() can be used
-to retrieve single keys. See Config library documentation for more
-information.
+The :doc:`Config Library <../libraries/config>` is the preferred way of
+accessing configuration information, however ``config_item()`` can be used
+to retrieve single keys. See :doc:`Config Library <../libraries/config>`
+documentation for more information.
+
+.. important:: This function only returns values set in your configuration
+ files. It does not take into account config values that are
+ dynamically set at runtime.
show_error('message'), show_404('page'), log_message('level', 'message')
========================================================================