<Ui xmlns="http://www.blizzard.com/wow/ui/">
  <Frame name="Atr_Mask" toplevel="true" parent="UIParent" enableMouse="true" hidden="true">
    <Backdrop bgFile="Interface\Tooltips\UI-Tooltip-Background" tile="true">
      <TileSize><AbsValue val="16"/></TileSize>
    </Backdrop>

    <Scripts>
      <OnLoad>
        self:SetBackdropColor( 0.2, 0.2, 0.2 )
      </OnLoad>
      <OnShow>
        self:SetPoint( "TOPLEFT", "AuctionFrame", "TOPLEFT" )
        self:SetPoint( "BOTTOMRIGHT", "AuctionFrame", "BOTTOMRIGHT", 0, -20 )
        self:SetFrameStrata( "HIGH" )
      </OnShow>
    </Scripts>
  </Frame>
</Ui>