This does not happen in ClarisWorks version 2.0.
Sometimes it seems as if ClarisWorks 1.0 can lose the contents of the clipboard. To demonstrate this:
1) Make sure another application is running while in System 7 or 6.x with MultiFinder
2) Launch ClarisWorks and open a document (preferably in the Graphics environment)
3) Open the Scrapbook and copy something to the Clipboard
4) Paste picture into ClarisWorks document-no problem.
5) Switch to the other application and then back to ClarisWorks
6) Try pasting picture. Nothing happens. It seems as though the contents of the clipboard have been erased although you will be able to paste the picture into your other open application
This issue will not happen if you copy a picture from ClarisWorks to the Clipboard and move between applications. Additionally, after you perform step 4, open the clipboard from ClarisWorks. When you switch applications in Step 5 and return to ClarisWorks, the clipboard window will still show the picture you copied even though you can't paste it. Close the window and open it again and you will have an empty Clipboard window.
Likely Explanation & Workaround:
In both System 7 and System 6 with MultiFinder, applications have the opportunity to check to see whether the contents of the clipboard have changed when responding to suspend and resume events (sent when you move between applications) so that the state of the Clipboard is properly handled.
In all likelihood, ClarisWorks is misinterpreting some of these events (probably the resume event) so returning to the application replaces the contents of the scrapbook with ClarisWorks empty private scrap. That's why copying a picture from ClarisWorks will not duplicate the problem-it's private scrap is not empty. On the positive side, it still manages it's responsibilities when you go to another application properly-that's why the contents of the Clipboard are OK when you go back to another application.
Additionally, according to Inside Macintosh, the clipboard window should be hidden when switching applications.