As wxStaticBox can now contain child windows, derive it from wxNavigationEnabled<> to allow TAB-navigating among them. Without this, it was impossible to switch focus from keyboard to any of the controls inside wxStaticBox. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72523 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775