diff --git a/lib/galaxy/tool_util/xsd/galaxy.xsd b/lib/galaxy/tool_util/xsd/galaxy.xsd
index 7f32306bdde..fa436411505 100644
--- a/lib/galaxy/tool_util/xsd/galaxy.xsd
+++ b/lib/galaxy/tool_util/xsd/galaxy.xsd
@@ -4121,7 +4121,7 @@ used to generate dynamic options.
     </xs:attribute>
     <xs:attribute name="startswith" type="xs:string">
       <xs:annotation>
-        <xs:documentation xml:lang="en">Ignore lines starting with the given string.</xs:documentation>
+        <xs:documentation xml:lang="en">Keep only lines starting with the given string.</xs:documentation>
       </xs:annotation>
     </xs:attribute>
     <xs:attribute name="meta_file_key" type="xs:string">
diff --git a/lib/galaxy/tools/parameters/dynamic_options.py b/lib/galaxy/tools/parameters/dynamic_options.py
index 803d54349f6..878236325a5 100644
--- a/lib/galaxy/tools/parameters/dynamic_options.py
+++ b/lib/galaxy/tools/parameters/dynamic_options.py
@@ -645,7 +645,7 @@ class DynamicOptions:
         rval = []
         field_count = None
         for line in reader:
-            if line.startswith("#") or (self.line_startswith and line.startswith(self.line_startswith)):
+            if line.startswith("#") or (self.line_startswith and not line.startswith(self.line_startswith)):
                 continue
             line = line.rstrip("\n\r")
             if line:
diff --git a/test/functional/tools/select_from_csvdataset.xml b/test/functional/tools/select_from_csvdataset.xml
index 6ca646a1db3..e1e1aac443d 100644
--- a/test/functional/tools/select_from_csvdataset.xml
+++ b/test/functional/tools/select_from_csvdataset.xml
@@ -6,7 +6,7 @@ echo select_single '$select_single' > '$output'
     <inputs>
         <param name="single" type="data" format="csv" label="single"/>
         <param name="select_single" type="select" label="select_single">
-            <options from_dataset="single" separator="," startswith="Transaction_date">
+            <options from_dataset="single" separator="," startswith="1/3/09">
                 <column name="name" index="1"/>
                 <column name="value" index="2"/>
                 <validator type="no_options" message="No data is available in single" />
@@ -29,11 +29,15 @@ echo select_single '$select_single' > '$output'
                 </assert_contents>
             </output>
         </test>
-        <!-- test that data from "comment" lines can not be selected, i.e. if the startswith attribute of <options> works-->
+        <!-- test that only data from lines starting with "1/2/09" can be selected, i.e. if the startswith attribute of <options> works-->
         <test expect_failure="true">
             <param name="single" value="1.csv" />
             <param name="select_single" value="Product" />
         </test>
+        <test expect_failure="true">
+            <param name="single" value="1.csv" />
+            <param name="select_single" value="Product2" />
+        </test>
     </tests>
     <help>
     </help>