refactoring to common code for focus set and lost events, so that changes can be made a single place, see #14269

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76575 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
refactoring to common code for updating selections, using common focus code, see #14269

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76576 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775