MFC功能包 - 可停靠文件资源管理器和可停靠属性窗口

I'm new to MFC and is a bit confused with the new features of "MFC feature pack." Through the wizard I now have an application that looks like an IDE - has a dockable file explorer on the left side and a dockable properties window on the right side. I'm already able to get the selected items on the file explorer window through ON_WM_LBUTTONDBLCLK and GetItemText().I'm new to MFC and is a bit confused with the n