That may not do it (check under security).
Otherwise,
Tools > Protection > Protect and Share workbook
That may not do it (check under security).
Otherwise,
Tools > Protection > Protect and Share workbook
Software: LibreOffice 3.3 on Mac OS X 10.6.5
(retired Excel 2003 user, 3.28.2008)
Humanware: Older than dirt
--------------------
old, slow, and confused
but at least I'm inconsistent!
Rich