diff --git a/lib/galaxy/tool_util/xsd/galaxy.xsd b/lib/galaxy/tool_util/xsd/galaxy.xsd
index 02d67e1c35b3..4672e08fa123 100644
--- a/lib/galaxy/tool_util/xsd/galaxy.xsd
+++ b/lib/galaxy/tool_util/xsd/galaxy.xsd
@@ -5619,7 +5619,12 @@ More information can be found on Planemo's documentation for
     </xs:attribute>
     <xs:attribute name="sort_by" type="xs:string" use="optional">
       <xs:annotation>
-        <xs:documentation xml:lang="en">A string `[reverse_][SORT_COMP_]SORTBY` describing the desired sort order of the collection elements. `SORTBY` can be `filename`, `name`, `designation`, `dbkey` and the optional `SORT_COMP` can be either `lexical` or `numeric`. Default is lexical sorting by filename.</xs:documentation>
+        <xs:documentation xml:lang="en"><![CDATA[
+        A string `[reverse_][SORT_COMP_]SORTBY` describing the desired sort order of the collection elements.
+        `SORTBY` can be `filename`, `name`, `designation`, `dbkey` and the optional `SORT_COMP` can be either
+        `lexical` or `numeric`. Default is lexical sorting by filename. 
+        Note that lexical sorting is case sensitive, i.e. upper case characters come before lower case characters (e.g. "Apple" < "Banana" < "apple" < "banana").
+        ]]></xs:documentation>
       </xs:annotation>
     </xs:attribute>
     <xs:attribute name="visible" type="xs:boolean" use="optional">