How can I filter no missing values in a special attribute

I m using the "Process documents from data" to select sentences containing a certain word. The operator generates an example set with a special attribute named text. Now I want to select only the records containing text, but what I trie it doesn't seem to work. I tried filter examples/no_missing values, but somehow I can't filter the recors out containing text. Anabody suggestions?

Regards Arno

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="6.0.003">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="6.0.003" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="read_excel" compatibility="6.0.003" expanded="true" height="60" name="Read Excel" width="90" x="45" y="75">
        <parameter key="excel_file" value="C:\Improve Your Business\Qing\Rapidminer\Hampshire hotel\Prediction model.xlsx"/>
        <parameter key="sheet_number" value="2"/>
        <parameter key="imported_cell_range" value="A1:F8"/>
        <parameter key="first_row_as_names" value="false"/>
        <list key="annotations">
          <parameter key="0" value="Name"/>
        </list>
        <list key="data_set_meta_data_information">
          <parameter key="0" value="Date.false.date_time.attribute"/>
          <parameter key="1" value="Rate.false.numeric.attribute"/>
          <parameter key="2" value="Guest category.false.binominal.attribute"/>
          <parameter key="3" value="Positivereview.true.text.attribute"/>
          <parameter key="4" value="Negativereview.true.text.attribute"/>
          <parameter key="5" value="Sentiment.true.attribute_value.label"/>
        </list>
      </operator>
      <operator activated="true" class="text:process_document_from_data" compatibility="5.3.002" expanded="true" height="76" name="Process Documents from Data" width="90" x="246" y="75">
        <parameter key="vector_creation" value="Term Occurrences"/>
        <parameter key="keep_text" value="true"/>
        <list key="specify_weights"/>
        <process expanded="true">
          <operator activated="true" class="text:tokenize" compatibility="5.3.002" expanded="true" height="60" name="Tokenize" width="90" x="112" y="30">
            <parameter key="mode" value="specify characters"/>
            <parameter key="characters" value=".:?!"/>
          </operator>
          <operator activated="true" class="text:filter_tokens_by_content" compatibility="5.3.002" expanded="true" height="60" name="Filter Tokens (by Content)" width="90" x="246" y="30">
            <parameter key="string" value="room"/>
          </operator>
          <connect from_port="document" to_op="Tokenize" to_port="document"/>
          <connect from_op="Tokenize" from_port="document" to_op="Filter Tokens (by Content)" to_port="document"/>
          <connect from_op="Filter Tokens (by Content)" from_port="document" to_port="document 1"/>
          <portSpacing port="source_document" spacing="0"/>
          <portSpacing port="sink_document 1" spacing="0"/>
          <portSpacing port="sink_document 2" spacing="0"/>
        </process>
      </operator>
      <operator activated="true" class="filter_examples" compatibility="6.0.003" expanded="true" height="94" name="Filter Examples" width="90" x="447" y="75">
        <parameter key="condition_class" value="no_missing_attributes"/>
        <list key="filters_list"/>
      </operator>
      <connect from_op="Read Excel" from_port="output" to_op="Process Documents from Data" to_port="example set"/>
      <connect from_op="Process Documents from Data" from_port="example set" to_op="Filter Examples" to_port="example set input"/>
      <connect from_op="Filter Examples" from_port="example set output" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>