Use ChildWindowFromPointEx(CWP_SKIPINVISIBLE) to ensure that we find the disabled children (by not using CWP_SKIPDISABLED). Add a unit test to check for the correct behaviour in all cases and document it. Closes #2942. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70794 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775