The Clipboard window is, in fact, a View (see The View). You can work with it in the same way as in a View (create graphic objects, manipulate them, ...). The only difference is that you are modifying the clipboard. But beware, editing the clipboard contents together with copy, cut and paste operations can be a bit confusing. For example, if you want to paste the clipboard contents in a page, only the selected objects will be pasted. If you copy some objects into the clipboard, the current clipboard contents will be deleted.