/indra/newview/skins/default/xui/en/widgets/view_border.xml

<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
<view_border name="view_border" 
             highlight_light_color="DefaultHighlightLight"
             highlight_dark_color="DefaultHighlightDark"
             shadow_light_color="DefaultShadowLight"
             shadow_dark_color="DefaultShadowDark"
             border_thickness="1"
             border_style="line"
             bevel_style="out"
             mouse_opaque="false"
             follows="all"/>