Merge pull request #1581 from adityamenon/develop

Added info about set_*() functions and form_validation class in  the Form Helper documentation.
diff --git a/user_guide_src/source/helpers/form_helper.rst b/user_guide_src/source/helpers/form_helper.rst
index a110f3c..fa7b3db 100644
--- a/user_guide_src/source/helpers/form_helper.rst
+++ b/user_guide_src/source/helpers/form_helper.rst
@@ -543,3 +543,7 @@
 	<input type="radio" name="myradio" value="1" <?php echo  set_radio('myradio', '1', TRUE); ?> />
 	<input type="radio" name="myradio" value="2" <?php echo  set_radio('myradio', '2'); ?> />
 
+.. note:: If you are using the Form Validation class, you must always specify a rule for your field,
+	even if empty, in order for the set_*() functions to work. This is because if a Form Validation object
+	is defined, the control for set_*() is handed over to a method of the class instead of the generic helper
+	function.
\ No newline at end of file