diff --git a/Bench4Q-Agent/src/main/java/org/bench4q/agent/plugin/dtd/ui.dtd b/Bench4Q-Agent/src/main/java/org/bench4q/agent/plugin/dtd/ui.dtd
index 22001564..3db6a373 100644
--- a/Bench4Q-Agent/src/main/java/org/bench4q/agent/plugin/dtd/ui.dtd
+++ b/Bench4Q-Agent/src/main/java/org/bench4q/agent/plugin/dtd/ui.dtd
@@ -48,7 +48,7 @@
 <!ELEMENT file EMPTY>
 <!ELEMENT date EMPTY>
 <!ELEMENT dropdownbox>
-
+<!-- values should be separated by ;-->
 <!ATTLIST dropdownbox
   values	CDATA		#REQUIRED
 >
\ No newline at end of file