When you save an Application, Window, DataWindow, or Menu or create a PowerBuilder Library, you can associate comments with the object or library.  Comments associated with an object display in the Select window when you open the painter and in the save window when you use Save As to save the object. 

To display the comments associated with a library, use the Comments option on the View menu in the Library painter.  When you turn this option on, the comments display for the library and when you expand the library the comments associated with the objects in the library also display.

You can add and modify the comments in the Library Painter and when you use Save As to save an object.