fgdata/gui/dialogs/chat_full.xml

<?xml version="1.0"?>

<PropertyList>
  <name>chat_full</name>
  <modal>false</modal>
  <layout>vbox</layout>

  <text>
    <label>Multiplayer Chat</label>
  </text>

  <hrule/>

  <textbox>
    <halign>fill</halign>
    <pref-width>550</pref-width>
    <pref-height>120</pref-height>
    <slider>20</slider>
    <live>true</live>
    <wrap>true</wrap>
    <editable>false</editable>
    <property>/sim/multiplay/chat_history</property>
  </textbox>

  <text>
    <label></label>
  </text>

  <group>
    <layout>hbox</layout>
   
    <input>
     <name>compose</name>   
     <stretch>true</stretch>
     <halign>fill</halign>
     <length>50</length>
     <pref-width>500</pref-width>  
     <property>/sim/multiplay/chat_compose</property>
    </input>   

    <button>
      <legend>Send</legend>
      <default>true</default>
      <key>Enter</key>
      <binding>
        <command>dialog-apply</command>
      </binding>
      <binding>
        <command>nasal</command>
        <script>
          var lchat = getprop("/sim/multiplay/chat_compose");
          if (lchat != "")
          {
            setprop("/sim/multiplay/chat", lchat);
            setprop("/sim/multiplay/chat_compose", "");
            fgcommand("dialog-update", props.Node.new({"object-name": "compose",
                                                       "dialog-name": "chat_full"}));
          }          
        </script>
      </binding>
    </button>
  </group>


  <text>
    <label></label>
  </text>

  <group>
    <layout>hbox</layout>
    <empty><stretch>true</stretch></empty>

    <button>
      <legend>Close</legend>
      <default>true</default>
      <key>Esc</key>
      <binding>
        <command>dialog-close</command>
      </binding>
    </button>
    
    <button>
      <legend>Less ^</legend>
      <default>false</default>
      <binding>
       <command>dialog-show</command>
       <dialog-name>chat</dialog-name>
      </binding>
      <binding>
        <command>dialog-close</command>
      </binding>
    </button>
    
    

    <empty><stretch>true</stretch></empty>
  </group>
</PropertyList>