set role operator problem

Why parameter "name" of "set role" operator not highlighting( that is , its not showing the attributes of my "read file "(excell file) operator).
Read file operator executing properly if i connect directly to output and showing the attributes in result window, but "set role" operator connected to "readfile operator", not working. still its asking in fixes "Change value of parameter "name" to...", if i fill forcefully the parameter "name" with my attribute "class" and parameter "target role" as "label" , if i try to execute , still its not working. The same problem some times arises with "select attribute" operator
Give me solution how to make the "set role" operator highlights the attributes of "read file" at name parameter when i click the set role operator.

here is xml code

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.2.008">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.2.008" expanded="true" name="Process">
    <process expanded="true" height="404" width="815">
      <operator activated="true" class="read_excel" compatibility="5.2.008" expanded="true" height="60" name="Read Excel" width="90" x="45" y="75">
        <parameter key="excel_file" value="C:\Users\asdf\Desktop\heart\Thesis work\Results\Cluster\2 clusterrs\clu0,1.xlsx"/>
        <list key="annotations"/>
        <list key="data_set_meta_data_information"/>
      </operator>
      <operator activated="true" class="set_role" compatibility="5.2.008" expanded="true" height="76" name="Set Role" width="90" x="313" y="75">
        <list key="set_additional_roles"/>
      </operator>
      <connect from_op="Read Excel" from_port="output" to_op="Set Role" to_port="example set input"/>
      <connect from_op="Set Role" from_port="example set output" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="54"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>

Thanking you

David