浮动工具条，数据树 本代码是数据树的实现，数据树能够自由浮动，就像VC界面一样-Floating toolbar, the data tree this code is the realization of the data tree, data tree can float, just like VC interface

在C++MFC框架应用程序里,当浮动工具条被拖离主窗口后,(In c + + MFC application framework, when the floating toolbar was dragged away from the main window,)