Implemented by user, no special support needed from operating system, programming design of overlay structure is complex.
由用户执行，不需要操作系统的特别支持，覆盖结构的程序设计很复杂。
2
An input widget of a special kind. Goto Anything is an overlay.
一种特殊的输入控件。快速跳转就是一种覆盖层控件。
3
PPT2010 added four shape tool, can cut the multi-channel graphics overlay, disappear to draw together the special shape, very simple character tagging box drawing change easily.