--- a/multijoin.xml	Thu Sep 05 11:42:27 2013 -0400
+++ b/multijoin.xml	Thu Sep 05 12:42:48 2013 -0400
@@ -7,6 +7,7 @@
         $ignore_dups
         $output_header
         $input_header
+        $first_filename
         #for $file in $files
             '$file.filename'
         #end for
@@ -14,21 +15,17 @@
   </command>
 
   <inputs>
-    <repeat name="files" title="file to join" min="2">
-        <param name="filename" label="Add file" type="data" format="txt" />
+
+    <param name="first_filename" label="File to join" type="data" format="txt" />
+    <repeat name="files" title="with" min="2">
+        <param name="filename" label="add additional file" type="data" format="txt" />
     </repeat>
 
     <param name="key_column" label="Common key column" type="integer"
        value="1" help="Usually gene-ID or other common value" />
 
-    <param name="value_columns" label="Column with values to preserve" type="text"
-       value="2,3,4" help="Enter comma-separated list of columns, e.g. 3,6,8">
-        <sanitizer>
-            <valid initial="string.printable">
-                <remove value="&apos;"/>
-            </valid>
-        </sanitizer>
-    </param>
+    <param name="value_columns" label="Column with values to preserve" 
+        type="data_column" data_ref="first_filename" accept_default="true" multiple="True" display="checkboxes"/>
 
     <param name="output_header" type="boolean" checked="false" truevalue="--out-header" falsevalue="" label="Add header line to the output file" help="" />
     <param name="input_header" type="boolean" checked="false" truevalue="--in-header" falsevalue="" label="Input files contain a header line (as first line)" help="" />