/indra/newview/skins/default/xui/en/floater_im_session.xml

<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
<floater
 legacy_header_height="18"
 background_visible="true"
 default_tab_group="1"
 height="355"
 help_topic="floater_im_box"
 layout="topleft"
 name="panel_im"
 can_dock="false"
 can_minimize="true"
 can_close="true"
 visible="false"
 width="394"
 can_resize="true"
 min_width="250"
 min_height="190">
  <layout_stack
   animate="true" 
   default_tab_group="2"
  follows="all"
  height="320"
  width="394"
  layout="topleft"
  orientation="horizontal"
  name="im_panels"
  tab_group="1"
  top="20"
  left="0">
    <layout_panel
      name="im_control_panel_holder"
      min_width="115"
      width="150" 
      height="320" 
      auto_resize="false">
      <panel
        name="panel_im_control_panel"
        layout="topleft"
        height="320"
        width="150" 
        follows="all"/>
      </layout_panel>
    <layout_panel
       default_tab_group="3"
       left="0"
       tab_group="2"
       top="0"
       height="200"
	     width="254"
       user_resize="true">
        <button
          height="20"
          follows="left|top"
          top="0"
          left="2"
          image_overlay="TabIcon_Open_Off"
          layout="topleft"
          width="25"
          name="slide_left_btn" />
         <button
          height="20"
          follows="left|top"
          top="0"
          left="2"
          image_overlay="TabIcon_Close_Off"
          width="25"
          name="slide_right_btn" />
        <chat_history
	 font="SansSerifSmall"
         follows="left|right|top|bottom"
         height="150"
         name="chat_history"
         parse_highlights="true"
         parse_urls="true"
        left="1"
         width="249">
        </chat_history>
        <line_editor
         bottom="0"
         follows="left|right|bottom"
	 font="SansSerifSmall"
         height="20"
         label="To"
         layout="bottomleft"
         name="chat_editor"
         tab_group="3"
         width="249">
        </line_editor>
    </layout_panel>
  </layout_stack>
</floater>