specify which background brush should be used for its children and each child may also choose to use either background brush or (solid) background colour wxWindow::OnEraseBackground() and wxControl::MSWControlColor() now use the same code git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@30976 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775