You enter the name of the class you want to browse in the Class text box. You can type in a class name explicitly, or you can transfer a class to the Class Browser using the Class standard action command in another tool, or by pasting a class in explicitly.
Note: You can use Edit > Paste to paste a class name into this area, even if the clipboard currently contains the string representation of the class name, rather than a class object itself. This lets you copy class names from other applications directly into the Class Browser. See Using the Object operations with the clipboard for a complete description of the way the LispWorks IDE clipboard operates.
LispWorks IDE User Guide (Windows version) - 25 Nov 2011