Actually the SearchLayoutStyle in shellstyle.dll has a gradient that is partly Toolbars, Headers and Rebar > Rebar > Communications > EdgeHighlightColor:Color or (Communications:: Rebar, 0, 0, 3805) which makes sense.
But Toolbars, Headers and Rebar > Rebar > Communications > TextColor:Color for a background like in my picture makes no sense at all.
Thanks anyway