I have created a worksheet in which users enter data in various fields
via dropdown lists. These dropdown lists were made using Excel's
standard data validation procedu Data|Validation|Settings --
Allow:List -- Source:=A range of cells named "Dates", on a separate
worksheet.

It was discovered that users could bypass this validation by pasting
data copied from another cell. We were happy to find that by
protecting the worksheet users could still use the dropdown lists to
enter values, but were unable to paste other values into these cells.

This was true for Excel 2000 on Windows 2000. But a couple of users
have tried running this file on Windows XP with Excel 2003. They are
unable to enter data via the dropdown lists unless the sheet protection
is removed.

Does anyone know why?